APA (7th ed.) Citation

Freeman, E., & Freeman, E. (2006). Head first HTML with CSS & XHTML. O'Reilly.

Chicago Style (17th ed.) Citation

Freeman, Elisabeth, and Eric Freeman. Head First HTML with CSS & XHTML. Sebastopol, Calif.: O'Reilly, 2006.

MLA (8th ed.) Citation

Freeman, Elisabeth, and Eric Freeman. Head First HTML with CSS & XHTML. O'Reilly, 2006.

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