Harvard Business School. (2011). Increasing Customer Loyalty. Harvard Business.
Chicago-referens (17:e uppl.)Harvard Business School. Increasing Customer Loyalty. Boston: Harvard Business, 2011.
MLA-referens (9:e uppl.)Harvard Business School. Increasing Customer Loyalty. Harvard Business, 2011.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.