Não informado. (1953). Contributions from the Perkins Observatory. Ohio State University, Ohio Wesleyan University.
Čikaški stil citiranja (17. izdanje)Não informado. Contributions from the Perkins Observatory. Delaware, Ohio: Ohio State University, Ohio Wesleyan University, 1953.
MLA način citiranja (8. izdanje)Não informado. Contributions from the Perkins Observatory. Ohio State University, Ohio Wesleyan University, 1953.
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