Cita APA (7th ed.)

Hartsfield, N., & Ringel, G. (1990). Pearls in graph theory: A comprehensive introduction. Academic Press.

Cita Chicago (17th ed.)

Hartsfield, Nora, i Gerhard Ringel. Pearls in Graph Theory: A Comprehensive Introduction. Boston: Academic Press, 1990.

Cita MLA (9th ed.)

Hartsfield, Nora, i Gerhard Ringel. Pearls in Graph Theory: A Comprehensive Introduction. Academic Press, 1990.