Crane, Donald P.
Kent publishing company, 1986
Buku Teks
consultant editor, Michael Armstrong
AP Information Services, 1997
Buku Referensi
Mondy, R. Wayne, author
Prentice-Hall, 2010
Buku Teks
edited by M. Ronald Buckley, Anthony R. Wheeler, Jonathon R. B. Halbesleben
Emerald, 2017
eBooks
Bohlander, George W., author
Thomson, 2004
Buku Teks