APA-referens (7:e uppl.)

Não informado. (1935). Contributions from the Perkins Observatory. Ohio State University, Ohio Wesleyan University.

Chicago-referens (17:e uppl.)

Não informado. Contributions from the Perkins Observatory. Delaware, Ohio: Ohio State University, Ohio Wesleyan University, 1935.

MLA-referens (8:e uppl.)

Não informado. Contributions from the Perkins Observatory. Ohio State University, Ohio Wesleyan University, 1935.

Varning: dessa hänvisningar är inte alltid fullständigt riktiga.