Não informado. (1935). Contributions from the Perkins Observatory. Ohio State University, Ohio Wesleyan University.
Παραπομπή σε μορφή Chicago (17η εκδ.)Não informado. Contributions from the Perkins Observatory. Delaware, Ohio: Ohio State University, Ohio Wesleyan University, 1935.
Παραπομπή σε μορφή MLA (8th εκδ.)Não informado. Contributions from the Perkins Observatory. Ohio State University, Ohio Wesleyan University, 1935.
Πρόσοχή: Οι παραπομπές μπορεί να μην είναι 100% ακριβείς.