APA (7th ed.) Citation

Christensen, C., & Rock, J. F. (1931). Asiatic Pteridophyta collected by Joseph F. Rock, 1920-1924. U.S. Government Printing Office.

Chicago Style (17th ed.) Citation

Christensen, Carl, and Joseph F. Rock. Asiatic Pteridophyta Collected by Joseph F. Rock, 1920-1924. [Place of publication not identified]: U.S. Government Printing Office, 1931.

MLA (9th ed.) Citation

Christensen, Carl, and Joseph F. Rock. Asiatic Pteridophyta Collected by Joseph F. Rock, 1920-1924. U.S. Government Printing Office, 1931.