एपीए उद्धरण

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

शिकागो स्टाइल उद्धरण

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

एमएलए उद्धरण

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