Lewicki, Roy J.
McGraw-Hill, 2000
Buku Teks
Roy J. Lewicki, Saunders David M., Minton John W., Barry Bruce
McGraw-HIll, 2003
Buku Teks
Woll, Peter
Longman , 2001
Buku Teks
Herbert, Theodore T.
Macmillan, 1976
Buku Teks
Hansen, Harry L.
Richard D. Irwin, 1964
Buku Teks