APA-referens (7:e uppl.)
Stettler, R. F. (2009). Cottonwood and the river of time: On trees, evolution, and society. University of Washington Press.
Chicago-referens (17:e uppl.)
Stettler, R. F. Cottonwood and the River of Time: On Trees, Evolution, and Society. Seattle: University of Washington Press, 2009.
MLA-referens (9:e uppl.)
Stettler, R. F. Cottonwood and the River of Time: On Trees, Evolution, and Society. University of Washington Press, 2009.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.