APA (7th ed.) Citation

Riordan, R. (2009). The demigod files (First edition.). Disney/Hyperion Books for Children.

Chicago Style (17th ed.) Citation

Riordan, Rick. The Demigod Files. First edition. New York: Disney/Hyperion Books for Children, 2009.

MLA (8th ed.) Citation

Riordan, Rick. The Demigod Files. First edition. Disney/Hyperion Books for Children, 2009.

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