Robert Spector, Patrick D. McCarthy (2012). “The Nordstrom Way to Customer Service Excellence: The Handbook For Becoming the "Nordstrom" of Your Industry”, p.29, John Wiley & Sons
Robert Spector, Patrick D. McCarthy (2012). “The Nordstrom Way to Customer Service Excellence: The Handbook For Becoming the "Nordstrom" of Your Industry”, p.9, John Wiley & Sons