Irwin, 1989
Buku Teks
Carrell, Michael R., author
Macmillan, 1992
Buku Teks
Milkovich, George T., author
Tex Business Publications , 1985
Buku Teks
Odiorne, George S.
Dow Jones-Irwin , 1982
Buku Teks
Strauss, George, author
Prentice-Hall, 1980
Buku Teks