APA (7th ed.) Citation

Zylstra, E. R., & Swann, D. E. (2009). A history of desert tortoise research at Saguaro National Park (Version 4 (4/6/2009).). U.S. Department of the Interior, National Park Service, Natural Resource Program Center.

Chicago Style (17th ed.) Citation

Zylstra, Erin R., and Don E. Swann. A History of Desert Tortoise Research at Saguaro National Park. Version 4 (4/6/2009). Fort Collins, Colorado: U.S. Department of the Interior, National Park Service, Natural Resource Program Center, 2009.

MLA (9th ed.) Citation

Zylstra, Erin R., and Don E. Swann. A History of Desert Tortoise Research at Saguaro National Park. Version 4 (4/6/2009). U.S. Department of the Interior, National Park Service, Natural Resource Program Center, 2009.