APA (7th ed.) Citation

Lenssen, P. (2008). Google Apps Hacks (1st edition.). O'Reilly Media, Inc..

Chicago Style (17th ed.) Citation

Lenssen, Philipp. Google Apps Hacks. 1st edition. O'Reilly Media, Inc., 2008.

MLA (9th ed.) Citation

Lenssen, Philipp. Google Apps Hacks. 1st edition. O'Reilly Media, Inc., 2008.

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