Meyer, Harold E., author
Prentice-Hall, 1992
Buku Referensi
Seglin, Jeffrey L., author
Amacom, 1996
Buku Referensi
Seglin, Jeffrey L., author
[American Management Association;;;, ], 2012
eBooks
Lamb, Charles W., author
J.M. Detn and Sons, 1950
Buku Teks
Abelard, Peter, author
Alfred A. Knopf, 1942
Buku Teks