APA (7th ed.) Citation

Critchfield, W. B. (1957). Geographic variation in Pinus contorta. Harvard Univ.

Chicago Style (17th ed.) Citation

Critchfield, William B. Geographic Variation in Pinus Contorta. Cambridge, Mass: Harvard Univ, 1957.

MLA (9th ed.) Citation

Critchfield, William B. Geographic Variation in Pinus Contorta. Harvard Univ, 1957.

Warning: These citations may not always be 100% accurate.