APA (7th ed.) Citation

Freeman, E., Robson, E., Bates, B., & Sierra, K. (2004). Head First Design Patterns (1st edition.). O'Reilly Media, Inc..

Chicago Style (17th ed.) Citation

Freeman, Eric, Elisabeth Robson, Bert Bates, and Kathy Sierra. Head First Design Patterns. 1st edition. O'Reilly Media, Inc., 2004.

MLA (9th ed.) Citation

Freeman, Eric, et al. Head First Design Patterns. 1st edition. O'Reilly Media, Inc., 2004.