Guba, E. G., & Lincoln, Y. S. (1981). Effective evaluation. Jossey-Bass Publishers.
Cita Chicago (17th ed.)Guba, Egon G., i Yvonna S. Lincoln. Effective Evaluation. San Francisco: Jossey-Bass Publishers, 1981.
Cita MLA (8th ed.)Guba, Egon G., i Yvonna S. Lincoln. Effective Evaluation. Jossey-Bass Publishers, 1981.
Atenció: Aquestes cites poden no estar 100% correctes.