Coyle, Diane, author
Texere, 2002
Buku Teks
Craven, John, 1949-, author
Blackwell, 1984
Buku Teks
Hera Susanti, author
Fakultas Ekonomi dan Bisnis Universitas Indonesia, 1986
UI - Skripsi (Membership)
Benham, Frederic, author
Pitman Publishing Corporation, 1941
Buku Klasik
Wonderling, David, author
Open University Press, 2005
Buku Teks