Key to genus Diplostephium, with descriptions of new species.

MLA

Blake, Sidney Fay. Key to Genus Diplostephium, with Descriptions of New Species. Washington: Govt. print. off., 1922.

APA

Blake, S. Fay. (1922). Key to genus Diplostephium, with descriptions of new species. Washington: Govt. print. off.

Chicago

Blake, Sidney Fay, Key to Genus Diplostephium, with Descriptions of New Species. Washington: Govt. print. off., 1922.