Harden, L., & Heyman, B. (2009). Digital engagement: Internet marketing that captures customers and builds intense brand loyalty. American Management Association.

Harden, Leland, and Bob Heyman. Digital Engagement: Internet Marketing That Captures Customers and Builds Intense Brand Loyalty. New York: American Management Association, 2009.

Harden, Leland, and Bob Heyman. Digital Engagement: Internet Marketing That Captures Customers and Builds Intense Brand Loyalty. American Management Association, 2009.