De Vrye, C. (1997). Good Service Is Good Bussiness 7 Simple Strategis For Succes. Jakarta: Gramedia Pustaka Utama.
Chicago Style aipamenaDe Vrye, Catherine. Good Service Is Good Bussiness 7 Simple Strategis For Succes. Jakarta: Gramedia Pustaka Utama, 1997.
MLA aipamenaDe Vrye, Catherine. Good Service Is Good Bussiness 7 Simple Strategis For Succes. Jakarta: Gramedia Pustaka Utama, 1997.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.