APA (7th ed.) Citation

Callahan, W. J. (1992). The enneagram for youth. The enneagram for youth.

Chicago Style (17th ed.) Citation

Callahan, William J. "The Enneagram for Youth." The Enneagram for Youth 1992.

MLA (8th ed.) Citation

Callahan, William J. "The Enneagram for Youth." The Enneagram for Youth, 1992.

Warning: These citations may not always be 100% accurate.