Παραπομπή APA

Nelsen, O. E. (1953). Comparative embroyology of the vertebrates.

Παραπομπή Chicago Style

Nelsen, Olin E. Comparative Embroyology of the Vertebrates. Blakiston Company, Inc., New York, 1953.

Παραπομπή MLA

Nelsen, Olin E. Comparative Embroyology of the Vertebrates. 1953.