Gaya APA

Palmer, H. (1988). The enneagram: Understanding yourself and the others in your life. Preface by Charles T. Tart. . San Francisco: San Francisco Harper & Row.

Gaya MLA

Palmer, Helen. "The enneagram: Understanding yourself and the others in your life. Preface by Charles T. Tart. ". San Francisco: San Francisco Harper & Row, 1988. Buku.