APA (7th ed.) Citation

Fritsch, R., & Fritsch, G. (1998). The four-color theorem: History, topological foundations, and idea of proof. Springer.

Chicago Style (17th ed.) Citation

Fritsch, Rudolf, and Gerda Fritsch. The Four-color Theorem: History, Topological Foundations, and Idea of Proof. New York: Springer, 1998.

MLA (9th ed.) Citation

Fritsch, Rudolf, and Gerda Fritsch. The Four-color Theorem: History, Topological Foundations, and Idea of Proof. Springer, 1998.