Hoppock, R. (1949). Group Guidance: Principles, techniques and evaluation. McGraw-Hill.
Cita Chicago (17th ed.)Hoppock, Robert. Group Guidance: Principles, Techniques and Evaluation. Nueva York: McGraw-Hill, 1949.
Cita MLA (9th ed.)Hoppock, Robert. Group Guidance: Principles, Techniques and Evaluation. McGraw-Hill, 1949.
Atenció: Aquestes cites poden no estar 100% correctes.