Alex Molnar. (2000). Vouchers: Class Size Reduction & Student Achievement. Phi Delta Kappa International Publishers.
Charles M. Achilles. (1999). Let's Put Kids First, Finally: Getting Class Size Right. Corwin Press.
Cooper, J.L., Robinson, P.R. And McKinney, M. (1994). Cooperative learning in the classroom. In D.F. Halpern & Associates Changing college classrooms: New teaching and learning strategies for an increasingly complex world. San Francisco: Jossey-Bass.
Enerson, Diane M., R. Neill Johnson, Susannah Milner, and Kathryn M. Plank. (1997). Teaching with Collaborative Activities and Small Groups. The Penn State Teacher II: Learning to Teach, Teaching to Learn. University Park: CELT, 57-72.