Παραπομπή APA

Hartmann, W. K. (1999). Moons and planets (4th ed.). Wadsworth.

Παραπομπή Chicago Style

Hartmann, William K. Moons and Planets. 4th ed. Belmont: Wadsworth, 1999.

Παραπομπή MLA

Hartmann, William K. Moons and Planets. 4th ed. Wadsworth, 1999.