Fink, Stephen L., author
Irwin, 1983
Buku Teks
Raed, Jane M., author
Chandos Publishing, 2003
Buku Teks
Callahan, Robert E.
Merrill , 1988
Buku Teks
Drucker, Peter F. (Peter Ferdinand), 1909-2005, author
Truman Talley Books/Plume, 1992
Buku Teks
Chattell, Alf
Macmillan, 1995
Buku Teks