1. Anderson, N. (1961). Work and leisure. New York: The Free Press of Glencoe.
2. Work Ethic, Daily Activities, and Retirement Satisfaction
3. Keller, M.(1981). Planning social recreation activities with older adults.Bloomington, IN: Indiana University.
4. Neulinger, J. (1981). The psychology of leisure (2nd ed.). Springfield, IL: Charles C Thomas.