Richard Henry Popkin. (1993). Philosophy made simple. New York: Doubleday.
Trích dẫn kiểu ChicagoRichard Henry Popkin. Philosophy Made Simple. New York: Doubleday, 1993.
MLA引文Richard Henry Popkin. Philosophy Made Simple. New York: Doubleday, 1993.
警告:這些引文格式不一定是100%准確.