APA (7th ed.) Citation

Ylla & Gregor, A. S. (1959). Animal babies. Harper.

Chicago Style (17th ed.) Citation

Ylla and Arthur S. Gregor. Animal Babies. New York: Harper, 1959.

MLA (9th ed.) Citation

Ylla and Arthur S. Gregor. Animal Babies. Harper, 1959.

Warning: These citations may not always be 100% accurate.