APA (7th ed.) Citation

Sully, K., & Elliot, R. (2009). Penguins can't fly. Alligator Books Ltd..

Chicago Style (17th ed.) Citation

Sully, Katherine, and Rebecca Elliot. Penguins Can't Fly. London: Alligator Books Ltd., 2009.

MLA (9th ed.) Citation

Sully, Katherine, and Rebecca Elliot. Penguins Can't Fly. Alligator Books Ltd., 2009.