De Vrye, C. (1997). Good Service Is Good Bussiness 7 Simple Strategis For Succes. Jakarta: Gramedia Pustaka Utama.
Dyfyniad Arddull ChicagoDe Vrye, Catherine. Good Service Is Good Bussiness 7 Simple Strategis For Succes. Jakarta: Gramedia Pustaka Utama, 1997.
Dyfyniad MLADe Vrye, Catherine. Good Service Is Good Bussiness 7 Simple Strategis For Succes. Jakarta: Gramedia Pustaka Utama, 1997.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.