Ballast, David Kent
Prentice-Hall, 1986
Buku Referensi
Aditya Herdiyan Pratama
Fakultas Ekonomi dan Bisnis Universitas Indonesia, 2020
UI - Tesis Membership
edited by John M. Lawler and Helen Aristar Dry
Routledge, 1998
Buku Teks
Davis, Elisabeth B.
Marcel Dekker, 1981
Buku Referensi
A. Fauzi Firdaus A.S.
Fakultas Ilmu Komputer Universitas Indonesia, 2014
UI - Tesis Membership