1. and ?Perspectives on Adult Learning: Framing Our Research.? In (ed.), Proceedings of the 40th Annual Adult Education Research Conference. De Kalb: Northern Illinois University, 1999.
2. New Direction;Colin,2001
3. and Intrinsic Motivation and Self-Determination in Human Behavior. New York: Plenum, 1985.
4. New Direction;Fenwick,2001