Citazione Stile APA (7a Edizione)

Hornaday, W. T. (1909). Popular official guide to the New York zoological park (10th ed.). New York Zoological Society.

Citazione stile Chigago Style (17a edizione)

Hornaday, William T. Popular Official Guide to the New York Zoological Park. 10th ed. New York: New York Zoological Society, 1909.

Citatione MLA (9a ed.)

Hornaday, William T. Popular Official Guide to the New York Zoological Park. 10th ed. New York Zoological Society, 1909.