Cita APA (7a ed.)

Humphrey, H. B. (1961). Makers of North American botany. Ronald Press.

Cita Chicago Style (17a ed.)

Humphrey, H. B. Makers of North American Botany. New York: Ronald Press, 1961.

Cita MLA (8a ed.)

Humphrey, H. B. Makers of North American Botany. Ronald Press, 1961.