Livingston, John Leslie, author
McGraw-Hill, 1970
Buku Teks
Artikel Jurnal
Elmaghraby, Salah E., author
John Wiley & Sons, 1977
Buku Teks
Lynch, Richard M., author
McGraw-Hill, 1983
Buku Teks
Kotler, Philip, author
Prentice Hall International, 1980
Buku Teks