Morgan, Chris
Berlin: Springer-Verlag, 1984
Buku Teks
Waterston, Albert, author
Johns Hopkins Press, 1962
Buku Teks
Beekun, Rafik Issa, author
International Institute of Islamic Thought, 2006
Buku Teks
Kotler, Philip, author
Prentice Hall International, 1991
Buku Teks
Kotler, Philip, author
Prentice-Hall, 1991
Buku Teks