1. Allen, N. J., & Rushton, J. P. (1983). Personality characteristics of community mental health volunteers: A review. Journal of Voluntary Action Research, 12, 36-49.
2. Clary, E.G., & Snyder, M. (1991). A functional analysis of altruism and prosocial behaviour: The case of volunteerism. In M. Clark (Ed.), Review of personality and social psychology (Vol. 12, pp. 119-148). Newbury Park, CA: Sage.
3. Clary, E. G., Snyder, M., & Stukas, A. A. (1996). Volunteers’ motivations: Findings from a national survey. Nonprofit and Voluntary Sector Quarterly, 25, 485-505.
4. Understanding and assessing the motivations of volunteers: A functional approach;Clary;Journal of Personality and Social Psychology,1998
5. De Palma, E. (2004). Azione volontaria e strategie organizzative. Come migliorare la presenza e la partecipazione dei volontari. Quaderni per il volontariato, www.cesvov.it , N.11.