Johnson, D. W., & Johnson, F. (1991). Joining together: Group theory and group skills (4th ed.). Prentice-Hall.
Chicago Style aipamenaJohnson, David W., and Frank Johnson. Joining Together: Group Theory and Group Skills. 4th ed. Englewood Cliffs, N. J: Prentice-Hall, 1991.
MLA aipamenaJohnson, David W., and Frank Johnson. Joining Together: Group Theory and Group Skills. 4th ed. Prentice-Hall, 1991.
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