Παραπομπή APA

Rossi, P. H., & Freeman, H. E. L. (1998). Evaluation- a systematic approach (6th ed.). Sage.

Παραπομπή Chicago Style

Rossi, Peter H., και Howard E. Lipsey Freeman. Evaluation- a Systematic Approach. 6th ed. London: Sage, 1998.

Παραπομπή MLA

Rossi, Peter H., και Howard E. Lipsey Freeman. Evaluation- a Systematic Approach. 6th ed. Sage, 1998.