Christensen, Howard B., author
Hoghton Mifflin, 1977
Buku Teks
Bluman, Allan G., author
McGraw-Hill, 2013
Buku Teks
Peacock, Janet L., auhtor
Oxford University Press, 2007
Buku Teks
Richman, Larry, author
[American Management Association, ], 2002
eBooks
Sartika Kurniali, author
PT Gramedia, 2009
Buku Teks