APA (7th ed.) Citation

Penenberg, A. L. (2009). Viral loop: From Facebook to Twitter, how today's smartest businesses grow themselves. Hyperion.

Chicago Style (17th ed.) Citation

Penenberg, Adam L. Viral Loop: From Facebook to Twitter, How Today's Smartest Businesses Grow Themselves. New York: Hyperion, 2009.

MLA (8th ed.) Citation

Penenberg, Adam L. Viral Loop: From Facebook to Twitter, How Today's Smartest Businesses Grow Themselves. Hyperion, 2009.