APA (7th ed.) Citation

Wherry, E. T. (1948). Guide to eastern ferns ([2d ed.].). University of Pennsylvania Press.

Chicago Style (17th ed.) Citation

Wherry, Edgar T. Guide to Eastern Ferns. [2d ed.]. Philadelphia: University of Pennsylvania Press, 1948.

MLA (9th ed.) Citation

Wherry, Edgar T. Guide to Eastern Ferns. [2d ed.]. University of Pennsylvania Press, 1948.