1. Bickman, L. (Ed.). (1987). Using program theory in evaluation. San Francisco Jossey-Bass.
2. Bickman, L. (Ed.). (1990). Advances in program theory. San Francisco: Jossey-Bass.
3. Campbell, D. T., & Stanley, J. (1963). Experimental and quasi-experimental designs for research. Chicago: RandMcNally.
4. Chen H.T./Donaldson, S. L./Mark, M. M. (2011). Validity Frameworks for Outcome Evaluation In C. HT, S. L. Donaldson & M. M. Mark (Eds.), Advancing Validity. In: Outcome Evaluation: Theory and Practice (Vol. Forthcoming). San Francisco: Jossey-Bass.
5. Chen, H. T. (1988). Validity in evaluation research: a critical assessment of current issues. Policy and Politics, 16(1), S. 1-16.