1. Allen, N. J., & Rushton, J. P. (1983). Personality characteristics of community mental health volunteers: A review. Nonprofit and Voluntary Sector Quarterly, 12(1), 36–49.
2. American Psychological Association. APA Dictionary of Psychology. https://dictionary.apa.org/psychology
3. American Sociological Association. What is Sociology? https://www.asanet.org/about/what-sociology
4. Auslander, G. K., & Litwin, H. (1988). Sociability and patterns of participation: Implications for social service policy. Nonprofit and Voluntary Sector Quarterly, 17(2), 25–37.
5. Bell, W., & Force, M. T. (1956). Urban neighborhood types and participation in formal associations. American Sociological Review, 21(1), 25–34.