LEVIN, H. L. (1983). The earth through time.-- ed.2. Saunders College.
芝加哥风格引文LEVIN, Harold L. The Earth Through Time.-- Ed.2. New York: Saunders College, 1983.
MLA引文LEVIN, Harold L. The Earth Through Time.-- Ed.2. Saunders College, 1983.
警告：这些引文格式不一定是100％准确.