APA (7th ed.) Citation

Dietrich, W., & Wagner, W. L. (1997). Systematics of Oenothera, section Oenothera, subsection Oenothera (Onagraceae). American Soc. of Plant Taxonomists.

Chicago Style (17th ed.) Citation

Dietrich, Werner, and Warren L. Wagner. Systematics of Oenothera, Section Oenothera, Subsection Oenothera (Onagraceae). Ann Arbor, Mich: American Soc. of Plant Taxonomists, 1997.

MLA (9th ed.) Citation

Dietrich, Werner, and Warren L. Wagner. Systematics of Oenothera, Section Oenothera, Subsection Oenothera (Onagraceae). American Soc. of Plant Taxonomists, 1997.