Workplace violence refers to incidents where workers are abused, threatened or assaulted, either by people from within or outside their workplace. Workplace violence may have severe negative consequences for the workers affected, their co-workers and families; as well as for organisations and the society as a whole. The aim of this article is to: present a conceptual framework of the phenomenon; outline and discuss the main types and antecedents to workplace violence; and, finally, provide an informed commentary on the methods and practices used to manage and, moreover, prevent this work-related issue.
Defining workplace violence
Violence is a complex and heterogeneous phenomenon. The perception of what constitutes violence is diverse in different contexts and cultures. The World Health Organisation defines violence as “the intentional use of physical force or power, threatened or actual, against oneself, another person, or against a group or community, which either results in or has a high likelihood of resulting in injury, death, psychological harm, maldevelopment, or deprivation" (pg.5) .
To date, no single, uniform definition of workplace violence has emerged. Most definitions of workplace violence refer to both physical and psychological acts. These acts of violence may range from minor cases of disrespect to criminal offences: including, homicide, physical assault, threat, verbal insult, harassment (bullying, mobbing), sexual harassment and discrimination
The International Labour Organisation (ILO) defines workplace violence as “… any action, incident or behaviour that departs from reasonable conduct in which a person is assaulted, threatened, harmed, injured in the course of, or as a direct result of, his or her work" (pg. 10) .
A definition for workplace violence was proposed during an expert meeting in 1995 organised by European Commission. The agreed definition is now the definition widely used by the European Commission, (European) institutions and researchers . Here workplace violence is defined as: “Incidents where persons are abused, threatened or assaulted in circumstances related to their work, including commuting to and from work, involving explicit or implicit challenges to their safety, well-being or health" (pg.1) . This definition includes a wide range of behaviours of both physical and psychological nature. Within this definition, there are several terms that can be, and moreover should be, further defined including, abuse, threat, and assault. The term abuse refers to “behaviours that depart from reasonable conduct and involve the misuse of physical or psychological strength; abuse covers all forms of harassment, including sexual and racial harassment, bullying and mobbing". Threat refers to “the menace of death, or the announcement of an intention to harm a person or to damage their property". “Assault" refers to “any attempt at physical injury or attack on a person including actual physical harm" (pg. 30) . Also, circumstances related to work are to be interpreted broadly. They include attacks towards workers while working on location, from home or during non-working hours as long as these attacks are somehow related to the job of a worker .
Types of workplace violence
In terms of the origin of the source of workplace violence, a distinction is often made between internal and external violence. Internal workplace violence takes place between workers. This can include, for example, aggressive behaviours between superiors and subordinates. External workplace violence or “third party violence", in contrast, is perpetrated by persons outside the organisation. This may be people with a direct link to the victim or the victims’ employer (such as, customers, clients, patients, a patient’s relative, passengers or students), but also people who have no such relation.
In a similar vein, some classifications distinguish between criminal violence (no relation between offender and victim), client initiated violence, co-worker violence (internal violence) and domestic violence (perpetrated within a work setting, by individuals who have a personal relationship with the victim). Some definitions of workplace violence, however, explicitly exclude violence among colleagues (internal violence) as well as domestic violence. Since the nature of these incidents may be totally different from that of third-party violence .
In terms of the sequence of aggressive behaviours, workplace violence may comprise of a one-off incident, but it may also consist of repeated or systematic actions. In 2008 the ILO stated: “these actions may be relatively minor by themselves, but the accumulation may come to constitute a serious form of workplace violence." (pg. 10) . This especially applies to bullying and sexual harassment.
How common is workplace violence?
Several countries collect national statistical information on workplace violence. However, prevalence rates are difficult to compare; because of the use of different definitions, different data collection and measurement methods, and differences in cultural contexts. The European Working Conditions Survey (EWCS) is an EU-wide survey conducted by the European Foundation for the Improvement of Living and Working Conditions, which systematically measures, among other aspects of working conditions, workplace violence as perceived by workers themselves. According to the EWCS conducted in 2010, 1.9% of the European workers (EU 27) had been subjected to physical violence at work in the past 12 months. This means that over 6 million workers are exposed per year. Verbal abuse was reported by 10.8% of all workers, while 5% had been subjected to threats and humiliating behaviour in the last month before the survey.
The EWCS found countries whose workers report a high prevalence of physical violence were France (3.8%), the United Kingdom (3.3%), Ireland (3.2%), Denmark (2.9%) and Belgium (2.9%). Low rates were found in Italy (0.2%), Lithuania (0.3%), Hungary (0.3%), Estonia (0.4%) and Cyprus (0.4%). At the organisational level, the first EU-wide Enterprise Survey of New and Emerging Risks (ESENER-1), conducted in 2009, found that Turkey (65%), Portugal (52%), Romania (44%), Bulgaria (32%) and Norway (26%) had the highest proportion of enterprises reporting major concern about violence or the threat of violence. On the other hand, Italy (4%), Hungary (3%), Slovenia (2%) and Estonia (2%) had the lowest proportion of enterprises reporting concern about those risks . The results published in the Summary of the Second European Survey Of Enterprises on New and Emerging Risks (ESENER-2) showed that “having to deal with difficult customers, patients, pupils, etc." (p.4) is the most frequently reported risk factor in education, human health and social work activities (75%) and trade, transport, food/accommodation and recreation activities (62%) . . This risk factor was also reported as the second in terms of frequency of reporting in public administration (68%) and IT, finance, real estate and other technical scientific or personal service activities (56%) . In addition, ESENER-2 results showed that whilst 55% of EU enterprises currently have a procedure in place to deal with ‘difficult customers, patients or pupils’, this continues to vary between individual countries . Such procedures are more prevalent in the UK, Sweden, Ireland, Finland, Netherlands, Norway, Slovenia, Denmark and Belgium (more than 60%) and the least common in Hungary, Bulgaria, Albania and Italy (30% and less) . The prevalence for each country should be interpreted with some caution, as they should be considered within a wider context. As the figures may be related and influenced by the level of awareness and the cultural norms in each European country. In general, it has been observed that incidence rates of reported physical violence, verbal abuse and threats of violence appear to be somewhat higher in the Northern European member states. It has been suggested that this might be related to the fact that many of countries that are characterised by large welfare service sectors, especially in health and social care .
According to previous surveys exposure to physical violence increased from 4% in 1995 to 6% in 2005 . Comparable national surveys have observed similar trends . However, because of the use of a different phrasing of the question used in the 2010 EWCS survey, it is difficult to draw conclusions on the nature and mechanisms underpinning the observed trends over time.
Who are at risk?
Violence can potentially affect any workplace and any worker. However, certain occupational groups appear to be more at risk than others. First of all, face-to-face interaction with clients, customers or others outside the work organisation increases the risk of violent incidents (i.e. ‘third party’ violence ). Typical high risk sectors include: education, healthcare and social work, public administration, transport and communication, and hotels and restaurants . Also, shop workers and assistants, especially in those in the retail sector, are at risk.
Young workers appear to be more at risk than older ones . There is mixed evidence concerning the role of gender . On the one hand, it is argued that because women are overrepresented in high-risk jobs, they are at greater risk of exposure to violence than men . However, on the other hand, studies in the healthcare sector reveal higher risk level for male, as compared to female workers  In general, women are more at risk of several other types of violence/ forms of discrimination; in particular, sexual harassment and victimisation.
Many different factors have been suggested to influence the risk of violence in the workplace. The risk factors for workplace violence have been studied by various scientific disciplines. The majority of studies on the antecedents of violence are not based on longitudinal, but rather on cross-sectional designs. The result of this paucity of research results in a limited degree to which causal relationships can be inferred. However, the available evidence highlights a number of individual, organisational and societal-level factors that have been found to be associated with higher exposure to workplace violence. From a micro to a macro perspective, the identified factors relating to the individual, organisational and societal levels will be discussed.
Apart from the demographic factors mentioned above, several individual level factors are believed to increase the risk of exposure to workplace violence: for example, lower levels of education and training, and shorter work experience . Also previous exposure to violence , inadequate conflict management skills  and low self-esteem  have been observed to be associated with a higher risk of workplace violence.
At the organisational level, a wide range of factors related to specific tasks or situations and the organisation of work in a broader context have been identified as potential antecedents of workplace violence. As mentioned above, face-to-face interaction with clients, customers or others outside the work organisation increases the risk of violent incidents. Especially those working with people in need of physical or emotional care, or with substance or drug addicted people are at greater risk. Other specific high-risk tasks and situations: including, evening and night work, shift work, working alone, working on location, handling valuables, exercising (physical) control over others, and specific physical design features of the workplace . Regarding the organisation of work in general, the potential for violence also arises when an employee needs to deny an individual’s request; to remonstrate with them; or when someone is requested to do something he/she does not want to do . In addition, technological innovation, the organisational (safety) climate, physical working conditions and, in particular, the psychosocial work environment have been linked to the risk of being subjected to violence . Conditions that may lead to higher stress levels in workers (such as, interpersonal conflicts, role ambiguity, low job control, time pressure, low quality of teamwork and high workloads) increase the risk of both external and internal violence in the workplace. It has been observed that the mechanisms underpinning these observed relationships may be different. For example, high strain work could directly or indirectly lead to lower job performance, which might evoke aggressive behaviour in customers, patients, and so on. In addition, the quality of health care (as perceived by patients), including long waiting times and satisfaction with treatment, has been linked to violence risks. Fatigue or stress resulting from high strain work might undermine the conflict management skills of workers. Finally, workers may actually be the instigators of violent interactions due to anger or frustration caused by working under strain .
A number of, partly empirically supported, societal or macro-level factors have been suggested to have an impact on workplace violence. These include cultural norms and values, individualisation, the embedment of violence in societies, globalisation, legislative frameworks, media-attention, and population density .
Violence at the workplace may have severe negative consequences for the targeted workers, their co-workers, families and friends, bystanders/witnesses, as well as to organisations and society as a whole.
Exposure to workplace violence may lead to both physical and psychological health problems . The physical consequences depend on the severity of the incident, and can range from minor injuries (e.g., bruising or wounds) to death. A review of 55 studies  on workplace violence found that psychological consequences include anxiety, fear, increased irritability, concentration problems, reduced self-confidence, sleeping problems, stress reactions, depression and post-traumatic stress disorder (PTSD). Moreover, other reported outcomes include personal safety concerns, job insecurity, fear, lowered job performance, job satisfaction, affective commitment, intent to turnover, physical well-being, interpersonal deviance, and organizational deviance.
According to the Fifth European Working Conditions Survey conducted in 2010  respondents who had been exposed to physical violence, when compared to those who had not been exposed, reported higher levels of stress (52% vs. 26%), fatigue (55% vs. 35%), sleeping problems (40% vs. 18%) and depression (27% vs. 8%). These effects remain very significant when controlling for other individual, workplace and background variables (occupation, sector, firm size, gender, age, tenure and country). The psychological effects of violence differ from person to person, and may be dependent on individual perception and coping strategies .
Beyond the negative health effects, exposure to violence may lead to adverse job attitudes (e.g. motivation or satisfaction) and may have behavioural outcomes (such as, absenteeism and reduced task performance). A review based on 55 independent studies (66 samples) by Hershcovis and Barling  found a relationship between ‘outsider aggression’ and three attitudinal outcomes (job satisfaction, affective commitment, and turnover intent), three behavioural outcomes (interpersonal deviance, organisational deviance and work performance) and four health-related outcomes (general health, depression, emotional exhaustion, and physical wellbeing). However, across the attitudinal and behavioural outcomes, stronger adverse effects were found for ‘supervisor aggression’ and ‘co-worker’ aggression. There were no observed differences for the majority of the health outcomes.
Findings from the Fifth European Working Conditions Survey  also indicate that absence rates due to work related ill health are significantly higher among those exposed to different forms of workplace aggression. Specifically, a higher proportion of workers exposed to physical violence, compared to the E-27 average, were absent for 10 or more days due to work-related ill-health (28% vs. 15%). It should be mentioned that not only the severity, but also the frequency of exposure to violence has been found to determine the consequences for victims (cumulative effects); this both applies to internal and external violence . Also, co-workers that are directly or indirectly involved in violent incidents might also suffer from adverse health and wellbeing outcomes. In addition, the results of exposure to various forms of violence are likely to affect the relatives and friends of a victim. Finally, bystanders/observers of workplace violence (both external and internal violence) might suffer from negative consequences as well.
For organisations the costs of violence are related to higher sickness absence rates, higher turnover rates (replacement costs and skills loss), reduced job satisfaction, motivation and productivity of victimised workers and their colleagues. Also, increased insurance premiums may result in economic loss for organisations . For example, in a study of aggression amongst teachers, schools in which teachers had strong shared concerns about aggression also had poorer shared job attitudes and poorer student outcomes  Similarly, a meta-analysis of 36 samples found that mistreatment climate (including violence, bullying and incivility) predicted exposure to mistreatment, motivation to reduce mistreatment, emotional strains, physical strains, organizational commitment, job satisfaction, and turnover intentions . Furthermore, there may be litigation costs in case of: a case of legal action against the perpetrator, grievance/compensation costs, property damage or damaged equipment, training costs, rehabilitation costs and loss of public goodwill and reputation .
Costs for society
For society, violence at work leads to increased pressure on social services and welfare. Particularly in cases were violence leads to permanent disability of victims. Hoel, Sparks and Cooper  estimated that the total economic burden of stress and violence at work may account for 1%-3.5% of the Gross Domestic Product (GDP). No separate estimation was made for workplace violence, however. The societal costs include benefits and welfare costs due to premature retirement, (long term) absenteeism and disability, costs of unemployment, medical costs and the loss of productivity . However, the exact costs may vary from country to country, depending upon the national health systems, regulatory frameworks and the social services available in these countries.
Types of interventions
Interventions for preventing and managing violence at work may focus on the individual, the individual-organisational interface, the job/task, organisation, or the societal/policy level. Interventions may also be classified as being primary, secondary or tertiary in nature, each serving different purposes. In primary interventions the goal is to eliminate or reduce exposure to violence. The aim of secondary interventions is to effectively manage violent incidents once they have occurred, and to minimise the consequences for the victims. Finally, tertiary interventions focus on the treatment and rehabilitation of workers who suffer from the consequences of exposure to violence . An overview of interventions at different levels and stages is presented below in Table 1.
Chappell and DiMartino suggest several strategies to tackle workplace violence. These include:
- a participative strategy and a (written) statement of intent;
- selection and screening
- Information and communication
- Physical environment and layout
- Protection-specific design
- Work organisation and job design
- Procedure for dealing with violent incidents: It is necessary for workers to be prepared.
- Procedures need to be established to defuse difficult situations and avoid violent confrontation.
- Guidelines for defusing aggression
- Immediate action after violent incidents
- Debriefing for the victims
- Monitoring and evaluation
Evaluating the effectiveness of workplace violence interventions, a review of nearly 100 interventions found that the vast majority of them were set within the retail or healthcare sectors . Risk assessments, work policies, training and management strategies obtained mixed results, although methodological limitations, including: limited sample size, lack of control groups, and high dropout rates, were identified. In addition, Wang, Hayes and O’Brien-Pallas  found that participation in a training or intervention program improved staff awareness of workplace violent incidents and their management skills, created “a more accepting, non-punitive attitude regarding [the problem of] violence towards staff" (p.21) and thus became a stimulus for staff to report violent incidents.
A comprehensive inventory of best practice interventions, practical advices and guidelines for the prevention and management of violence and harassment was completed by a European Project, called PRIMA-EF. The project provides evidence-based practical advice and guidance on the management and prevention of psychosocial risks: including, work related stress, bullying and harassment, and workplace violence .
The situation in Europe on the regulation of workplace violence is extremely varied and changing. EU bodies play a significant role in fostering new developments in this area. At the European level there are no legislative provisions which refer explicitly to violence and bullying at work. However, this is typically considered to fall implicitly within the scope of the EU framework directive on health and safety at work (Council Directive 89/391/EEC), and more specifically demonstrated by “sectoral and cross-industry social dialogue dealing with various aspects of working conditions" (pg. 57) . Some countries have introduced specific new legislation to tackle violence at the workplace (e.g. Sweden, France, Belgium, The Netherlands, Finland). In many cases this legislation covers both third party violence and (and in some cases only) internal violence (harassment, mobbing, bullying). In other cases (e.g., Ireland, UK, Germany) more general and already existing legislative frameworks (criminal, civil, health and safety) are considered to be sufficient. Some European countries (e.g., Denmark and Luxembourg) have implemented non-legislative measures: such as, codes of practices, regulations, and collective agreements .
One important development in preventing and managing violence at work is the Framework Agreement on Harassment and Violence at Work, adopted in 2007 by the European social partners ). With this agreement, European social partners condemn work related violence in all its forms, and recognise that violence can have an adverse effect on the workplace of each worker. The aim of this agreement is to increase awareness and understanding on the subject by employers, workers, and their representatives; as well as to provide them with an action oriented framework to identify, prevent, and manage workplace violence and harassment. The agreement clearly states that the responsibility to determine, examine and monitor the appropriate measures to tackle violence is with the employer in consultation with the workers and/or their representatives. According to the agreement, employers need to have a clear statement emphasising that harassment and violence will not be tolerated. Also, procedures outlining how to deal with violence should be specified. The agreement has led to several social dialogue initiatives: such as, the development of multi-sectoral guidelines to tackle third-party violence and harassment related to work.
In September 2010, multi-sectoral guidelines dealing with work-related violence and harassment from third parties, including: clients, patients and customers, were adopted by eight European social partner organisations, these included EPSU, UNI Europa, ETUCE, HOSPEEM, CEMR, EFEE, EuroCommerce and CoESS . These guidelines build on the 2007 Framework, recognising and focusing on violence and harassment carried out by third parties, not that of the victim’s colleagues.
 Krug, E.G., Dahlberg, L.L., Mercy, J.A., Zwi, A.B.,& Lozano, R. World report on violence and health. Geneva: World Health Organization, 2002. Available at: http://www.who.int/violence_injury_prevention/violence/world_report/en/
 Chappell, D., & Di Martino, V., Violence at work (3rd Edition), Geneva, Switzerland: ILO, 2006. Available at: http://www.ilo.org/public/libdoc/ilo/2006/106B09_110_engl.pdf
 Di Martino, V., Hoel, H., & Cooper, C., Preventing violence and harassment in the workplace. Dublin: European Foundation for the Improvement of Living and Working Conditions, 2003. Available at: http://www.eurofound.europa.eu/pubdocs/2002/109/en/1/ef02109en.pdf
 EU-OSHA - European Agency for Safety and Health at Work, Workplace Violence and Harassment: a European Picture, European Risk Observatory Literature Review, 2010. Available at: 
 Wynne, R., Clarkin, N., Cox, T., & Griffiths, A., Guidance on the prevention of violence at work, Luxembourg: European Commission, DG-V, 1997 (Ref. CE/VI-4/97).
 European Communities, Luxembourg, 2015. Available at: https://osha.europa.eu/en/tools-and-publications/publications/reports/esener-ii-summary.pdf/view
 Lehto, A-M., Violence, bullying and harassment in the workplace. Dublin: European Foundation for the Improvement of Living and Working Conditions, 2004. Available at: http://www.eurofound.europa.eu/ewco/reports/TN0406TR01/TN0406TR01.pdf
 Parent-Thirion, A., Macías, E.F., Hurley, J. & Vermeylen, G., Fourth European Working Conditions Survey, Dublin: European Foundation for the improvement of living and working conditions, 2007. Available at: http://www.eurofound.europa.eu/pubdocs/2006/98/en/2/ef0698en.pdf
 Estryn-Behar, M., van der Heijden, B., Camerino, D., Fry1, C., Le Nezet, O., Conway, P.M. & Hasselhorn, H-M., ‘Violence risks in nursing: results from the European ‘NEXT’ Study’, Occupational Medicine, Vol. 58, 2008, pp.107-114.
 Hahn, S. Zeller, A., Needham, I., Kok, G., Dassen, T., & Halfens, R. J. G., ‘Patient and visitor violence in general hospitals: A systematic review of the literature’, Aggression and Violent Behavior, Vol. 13, 2008, pp. 431-441.
 Hogh, A., Borg, V., & Mikkelsen, K.L., ‘Work-related violence as a predictor of fatigue: A 5-year follow-up of the Danish Work Environment Cohort Study’, Work & Stress, Vol. 17, 2003, pp. 182–194.
 Aquino, K., ‘Structural and individual determinants of workplace victimization: the effects of hierarchical status and conflict management style’, Journal of Management, Vol. 26, 2000, pp. 171–193.
 Harvey, S., & Keashley, L., ‘Predicting the risk for aggression in the workplace: risk factors, self-esteem and time at work’, Social Behavior and Personality, Vol. 31, 2003, pp. 807–814.
 Eurofound - European Foundation for the Improvement of Living and Working Conditions, ‘Physical and Psychological Violence at the Workplace’, Eurofound, Dublin, 2013. Available at: https://www.eurofound.europa.eu/publications/foundation-findings/2014/working-conditions/foundation-findings-physical-and-psychological-violence-at-the-workplace
 Calabro, K. & Baraniuk, S. ‘Organizational factors related to safety in a psychiatric hospital: employee perceptions’. AAOHN Journal: Official Journal of the American Association of Occupational Health Nurses, 51, 2003, pp. 425–432.
 Lawoko, S., Soares, J. J. F., & Nolan, P. ‘Violence towards psychiatric staff: A comparison of gender, job and environmental characteristics in England and Sweden.’ Work & Stress, 18, 2004, pp. 39-55.
 Leather, P., Claire, L., Beale, D., Cox, T., & Dickson, R.. ‘Exposure to occupational violence and the buffering effects of intra-organizational support’. Work & Stress, 12, 1998, pp. 161−178.
 Spector, P. E., Coulter, M. L., Stockwell, H. G., & Matz, M. W. ‘Perceived violence climate: A new construct and its relationship to workplace physical violence and verbal aggression, and their potential consequences.’ Work & Stress, 21, 2007, pp. 117–130.
 Yagil, D. ‘When the customer is wrong: A review of research on aggression and sexual harassment in service encounters’. Aggression and Violent Behavior, 13, 2008, pp. 141-152.
 Bayman, P. A., & Hussain, T. ‘Receptionists’ perceptions of violence in general practice’. Occupational Medicine, 57, 2007, pp 492–498.
 Camerino, D., Estryn-Behar, M., Conway, P.M., van der Heijden, B.I.J.M., & Hasselhorn, H-M. ‘Work-related factors and violence among nursing staff in the European NEXT Study: A longitudinal cohort study.’ International Journal of Nusring Studies, 45, 2008, pp 35-50.
 Hurrell, J.J., Worthington, K.A., & Driscoll, R.J. ‘Job stress, gender, and workplace violence: Analysis of assault experiences of state employees’. In G. R. VandenBos and E. Q. Bulatao (Eds), Violence on the job: Identifying risks and developing solutions. Washington: American Psychological Association, 1996, pp. 163-170.
 Schat, A.C., & Kelloway, E.K. ‘The effects of perceived control on the outcomes of workplace aggression and violence.’ Journal of Occupational Health Psychology, 5, 2000, pp. 386–402.
 Van Emmerik, I.J.H., Euwema, M.C., & Bakker, A.B. ‘Threats of workplace violence and the buffering effect of social support.’ Group and Organization Management, 32, 2007, pp 152-175.
 Piquero, N.L., Piquero, A.R., Craig, J.M., & Clipper, S.J., ‘Assessing research on workplace violence, 2000-2012.’ Aggression and Violent Behaviour, 18, 2013, pp. 383-394.
 Eurofound, Fifth European Working Conditions Survey, Publications Office of the European Union, Luxembourg, 2012. Available at: http://www.eurofound.europa.eu/sites/default/files/ef_publication/field_ef_document/ef1182en.pdf
 Hershcovis, M. S. & Barling, J., ‘Towards a multi-foci approach to workplace aggression: A meta-analytic review of outcomes from different perpetrators’, Journal of Organizational Behavior, Vol. 31, 2010, pp. 24–44.
 Wittmer, J.L.S., Sinclair, R.R., Martin, J.E., Tucker, J.S., & Lang, J. ‘Shared aggression concerns and organizational outcomes: The moderating role of resource constraints.’ Journal of Organizational Behaviour, 34, 2013, pp. 370-388.
 Yang, L.Q., Caughlin, D.E., Gazica, M.W., Truxillo, D.M., & Spector, P.E. ’Workplace Mistreatment Climate and Potential Employee and Organizational Outcomes: A Meta-Analytic Review From the Target’s Perspective.’ Journal of Occupational Health Psychology, 9, 3, 2014, pp. 315-335.
 Hoel, H., Sparks, K., & Cooper, C. L., The cost of violence/stress at work and the benefits of a violence/stress-free environment, report Commissioned by the International Labour Organisation, (ILO) Geneva, University of Manchester Institute of Science and Technology, 2001.
 Kompier, M.A.J., & Kristensen, T.S., ‘Organizational work stress interventions in a theoretical, methodological and practical context’, In J. Dunham (Ed). Stress in the workplace: Past, present and future, London: Whurr Publishers, 2001, pp. 164-190.
 Wassell, J.T. ’Workplace violence intervention effectiveness: A systematic literature review.’ Safety Science, 47, 2009, pp. 1059-1055.
 Wang, S., Hayes, L., & O’Brien-Pallas, L. ‘A review and evaluation of workplace violence prevention programs in the health sector.’ Nhsru, 2008 [2011-8-10]. Available at: http://tools.hhr-rhs.ca/index.php?option=com_mtree&task=viewlink&link_id=7339&Itemid=109&lang=en
 PRIMA-EF – Psychosocial Risk Management – Excellence Framework, Guidance on the European Framework for Psychosocial Risk Management, 2010. Available at:http://www.prima-ef.org/prima-ef.html
 European Social Dialogue. Framework Agreement on Harassment and Violence at Work, 26 April 2007. Available at: http://www.ueapme.com/docs/joint_position/2007_Framework_Agreement_Harassment_and_Violence_at_Work.pdf
 European Federation of Public Service Unions, ‘Multi-sectoral guidelines to tackle third-party violence and harassment related to work’, 2010. Available at: http://www.epsu.org/IMG/pdf/Final_Multi_sectoral_guidelines_-_20_07_10.pdf
European Commission. Preventing Workplace Harassment and Violence: Joint Guidance Implementing a European Social Partner Agreement, 2011. Available at: http://www.workplaceharassment.org.uk/
EU-OSHA - European Agency for Safety and Health at Work, Workplace Violence and Harassment: a European Picture. Office for Official Publications of the European Communities, Luxembourg, 2010. Available at:http://osha.europa.eu/en/publications/reports/violence-harassment-TERO09010ENC/view
EU-OSHA - European Agency for Safety and Health at Work, Facts 24: Violence at work, Office for Official Publications of the European Communities, Luxembourg, 2002. Available at: https://osha.europa.eu/en/tools-and-publications/publications/factsheets/24/view