(1988). The enneagram: Understanding yourself and the others in your life / Helen Palmer.
芝加哥风格引文The Enneagram: Understanding Yourself and the Others in Your Life / Helen Palmer. 1988.
MLA引文The Enneagram: Understanding Yourself and the Others in Your Life / Helen Palmer. 1988.
警告：这些引文格式不一定是100％准确.