References
- Johnson , D. W. and Johnson , R. T. 1991 . Learning together and alone , 3rd ed. , Boston : Allyn and Bacon .
- Slavin , R. 1995 . Cooperative learning , 2nd ed. , Needham Heights, MA : Allyn and Bacon .
- Wood , K. D. 1994 . Practical strategies for improving instruction , Columbus, OH : National Middle School Association .