APA (7th ed.) Citation

Avila, D. L., Combs, A. W., & Purkey, W. W. (1977). The helping relationship sourcebook (2nd ed.). Allyn and Bacon.

Chicago Style (17th ed.) Citation

Avila, Donald L., Arthur W. Combs, and William Watson Purkey. The Helping Relationship Sourcebook. 2nd ed. Boston: Allyn and Bacon, 1977.

MLA (9th ed.) Citation

Avila, Donald L., et al. The Helping Relationship Sourcebook. 2nd ed. Allyn and Bacon, 1977.