Reis, Matthew
American Management Association, 2010
eBooks
Wexley, Kenneth N.
Irwin, 1984
Buku Referensi
French, Wendell L.
Harper & Row, 1985.
Buku Teks SO
Greenberg, Jerald
Prentice-Hall, 2003
Buku Teks
Finlay, William W.
McGraw-Hill, 1955
Buku Teks