APA (7th ed.) Citation

Atwater, R., Lawson, R., & Atwater, F. (1938). Mr. Popper's penguins. Little, Brown and Company.

Chicago Style (17th ed.) Citation

Atwater, Richard, Robert Lawson, and Florence Atwater. Mr. Popper's Penguins. Boston: Little, Brown and Company, 1938.

MLA (9th ed.) Citation

Atwater, Richard, et al. Mr. Popper's Penguins. Little, Brown and Company, 1938.