Honomichl, Jack J.
Elex Media Komputindo , 1991
Buku Teks
Doman, Don
Gramedia Pustaka Utama, 1997
Buku Teks
Preston, Lee E.
IBER (Institute of Business and Economic Research), 1966
Buku Teks
Yoan Ferino
Fakultas Teknik Universitas Indonesia, 2005
UI - Skripsi (Membership)
Malhotra, Naresh K.
Indeks, 2006
Buku Teks