APA (7th ed.) Citation

Keck, D. D. (1932). Studies in Penstemon: A systematic treatment of the section Saccanthera. Univ. of California Press.

Chicago Style (17th ed.) Citation

Keck, David D. Studies in Penstemon: A Systematic Treatment of the Section Saccanthera. Berkeley: Univ. of California Press, 1932.

MLA (9th ed.) Citation

Keck, David D. Studies in Penstemon: A Systematic Treatment of the Section Saccanthera. Univ. of California Press, 1932.