Orr, P. D. (1971). Vertebrate Biology (tercera edición.). W.B. Sanders Company.
Chicago Style (17th ed.) CitationOrr, Ph. D. Vertebrate Biology. tercera edición. Philadelphia: W.B. Sanders Company, 1971.
MLA (9th ed.) CitationOrr, Ph. D. Vertebrate Biology. tercera edición. W.B. Sanders Company, 1971.
Warning: These citations may not always be 100% accurate.