Gaya APA

Riso, D, R., Hudson, R. (1999). The wisdom of the enneagram the complete guide to psychological and spiritual growth for the nine personality types . : bantam books.

Gaya MLA

Riso, Don, Richard., Hudson, Russ. "The wisdom of the enneagram the complete guide to psychological and spiritual growth for the nine personality types". : bantam books, 1999. Text.