Cita APA (7th ed.)

Critchfield, W. B. (1957). Geographic variation in Pinus Contorta. Harvard University.

Cita Chicago (17th ed.)

Critchfield, William Burke. Geographic Variation in Pinus Contorta. Cambridge, Mass.: Harvard University, 1957.

Cita MLA (8th ed.)

Critchfield, William Burke. Geographic Variation in Pinus Contorta. Harvard University, 1957.