Dyfyniad APA

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

Dyfyniad Arddull Chicago

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

Dyfyniad MLA

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

Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.