APA-Zitierstil (7. Ausg.)

Spier, F. S. (1975). The tree of knowledge: A study of the evolution of reason (1. ed.). Exposition Press.

Chicago-Zitierstil (17. Ausg.)

Spier, Fred S. The Tree of Knowledge: A Study of the Evolution of Reason. 1. ed. Hicksville, NY: Exposition Press, 1975.

MLA-Zitierstil (9. Ausg.)

Spier, Fred S. The Tree of Knowledge: A Study of the Evolution of Reason. 1. ed. Exposition Press, 1975.