Cita APA (7th ed.)

Guttman, B. S., & Hopkins, J. W. (1983). Understanding biology. Harcourt Jovanovich.

Cita Chicago (17th ed.)

Guttman, Burton S., i Johns W. Hopkins. Understanding Biology. New York: Harcourt Jovanovich, 1983.

Cita MLA (9th ed.)

Guttman, Burton S., i Johns W. Hopkins. Understanding Biology. Harcourt Jovanovich, 1983.