Sutherland, Max, author
PPM, 2004
Buku Teks
Sissors, Jack Z
NTC Businness Books, 1993
Buku Teks
Forceville, Charles
Routledge, 1996
Buku Teks
Reichert, Gene
Alexander Hamilton Institute, 1972
Buku Teks
Moriarty, Sandra E. (Sandra Ernst), author
Prentice Hall International, 1991
Buku Teks