APA (7th ed.) Citation

Walliams, D., & Ross, T. (2014). The first hippo on the moon. Harper Collins Children's Book.

Chicago Style (17th ed.) Citation

Walliams, David, and Tony Ross. The First Hippo on the Moon. London: Harper Collins Children's Book, 2014.

MLA (9th ed.) Citation

Walliams, David, and Tony Ross. The First Hippo on the Moon. Harper Collins Children's Book, 2014.