Berg, R. C., & Landreth, G. L. (1990). Group counseling: Concepts and procedures (2nd ed.). Accelerated Development Inc.
Chicago Style (17. basım) AtıfBerg, Robert C., ve Garry L. Landreth. Group Counseling: Concepts and Procedures. 2nd ed. Muncie, Ind: Accelerated Development Inc, 1990.
MLA (9th ed.) AtıfBerg, Robert C., ve Garry L. Landreth. Group Counseling: Concepts and Procedures. 2nd ed. Accelerated Development Inc, 1990.
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