Cherry, Paul
Questions that sell: the powerful process for discovering what your customer really wants
American Management Association, 2006
 eBooks
Cheverton, Peter
If you're so briliant... how come you can't identify your key customers=Kiat sukses seleksi pelanggan paling potensif/Peter Cheverton; penerjemah Andre Wiriadi
Elex Media Komputindo, 2003
 Buku Teks
Macaulay, Steve
How to improve your costumer service = kiat meningkatkan pelayanan bagi pelanggan / Steve Macaulay, Sarah Cook
Gramedia Pustaka Utama, 1997
 Buku Teks
Martin, Robert J.
Human relations for the hospitality industry
Van Nostrand Reinhold, 1991
 Buku Teks
Peppers, Don
Managing customer relationships : a strategic framework
John Wiley & Sons, 2011
 Buku Teks