1. Chase, P. & Doan, J. (1994). Full circle: A new look at multiage education. Portsmouth, NH: Heinemann.
2. De Lisi, R. & Golbeck, S. (1999). Implications of Piagetian theory for peer learning. In A.M. O'Donnell & A. King (Eds.), Cognitive perspectives on peer learning (pp. 3-37). Mahwah, NJ: Erlbaum.
3. Hogan, D.M. & Tudge, J.R. (1999). Implications of Vygotsky's theory for peer learning. In A.M. O'Donnell & A. King (Eds.), Cognitive perspectives on peer learning (pp. 39-65). Mahwah, NJ: Erlbaum.
4. Kagan, S. (1994). Cooperative learning. San Juan Capistrano, CA: Kagan Cooperative Learning.