Reichheld, F. (2011). The ultimate question 2.0: How net promoter companies thrive in a customer-driven world. Boston, Mass: Harvard Business Press.
Dyfyniad Arddull ChicagoReichheld, Fred. The Ultimate Question 2.0: How Net Promoter Companies Thrive in a Customer-driven World. Boston, Mass: Harvard Business Press, 2011.
Dyfyniad MLAReichheld, Fred. The Ultimate Question 2.0: How Net Promoter Companies Thrive in a Customer-driven World. Boston, Mass: Harvard Business Press, 2011.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.