Hardy, Gillian E. (2003), "The Impact of Psychological Distress on Absence From Work", Journal of Applied Psychology, 88, 306-314.
- Hardy, G.E., D.A. Shapiro, and C.E. Haynes (1999), "Validation of the General Health Questionnaire-12 using a sample of employees from the health care services", Psychological Assessment, 11, 159-165. [Endnote]
- Araya, R., R. Wynn, and G. Lewis (1992), "Comparison of two self-administered psychiatric questionnaires (GHQ-12 and SRQ-20) in primary care in Chile", Social Psyciatry and Psychiatric Epidemiology, 27, 159-165. [Endnote]
- Warr, P.B (1990), "The measurement of well-being and other aspects of mental health ", Journal of Occupational Psychology, 63, 193-210 . [Endnote]
- Warr, P. D., J. D. Cook, and T. D. Wall (1979), "Scales for the measurement of some work attitudes and aspects of psychological well-being.", Journal of Occupational Psychology, 52, 129–148. [Endnote]