APA

Walter H. E., Sayles L. P., . (1949). Biology of the vertebrates. New York: Macmillan Co.

Chicago

Walter Herbert Eugene, Sayles Leonard Perkins, . 1949. Biology of the vertebrates. New York: Macmillan Co.

Harvard

Walter H. E., Sayles L. P., . (1949). Biology of the vertebrates. New York: Macmillan Co.

MLA

Walter Herbert Eugene, Sayles Leonard Perkins, . Biology of the vertebrates. New York: Macmillan Co. 1949.