Gaya APA

Leon, J, &, P, C, H. (1974). Cliffs Notes on Heilbroner The Worldly Philosophers. . Lincoln: Lincoln Cliffs Notes.

Gaya MLA

Leon, Joseph, &, Patterson,, Charles, H.. "Cliffs Notes on Heilbroner The Worldly Philosophers. ". Lincoln: Lincoln Cliffs Notes, 1974. Buku.