APA (7th ed.) Citation

Atwater, R. a. F. Mr. Popper's Penguins.

Chicago Style (17th ed.) Citation

Atwater, Richard and Florence. Mr. Popper's Penguins.

MLA (8th ed.) Citation

Atwater, Richard and Florence. Mr. Popper's Penguins.

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