APA Citation

 Spence, A. (2006).  The unofficial guide to Photoshop CS2.  Wiley Pub., Inc.

Chicago Style Citation

 Spence, Alanna.  The Unofficial Guide to Photoshop CS2.  Wiley Pub., Inc, 2006.

MLA Citation

 Spence, Alanna.  The Unofficial Guide to Photoshop CS2.  Wiley Pub., Inc, 2006.

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