APA (7th ed.) Citation

Simon, F., & Ross, T. (2009). Horrid Henry's birthday party. Orion Children's Books.

Chicago Style (17th ed.) Citation

Simon, Francesca, and Tony Ross. Horrid Henry's Birthday Party. London: Orion Children's Books, 2009.

MLA (9th ed.) Citation

Simon, Francesca, and Tony Ross. Horrid Henry's Birthday Party. Orion Children's Books, 2009.