Sartain, Libby, author
[American Management Association, ], 2003
eBooks
Sihombing, Sonar, author
Elex Media Komputindo , 2006
Buku Teks
Claringbull, Norman, author
Learning Matters, 2010
Buku Teks
Shewfelt, Robert L., author
Springer, 2012
eBooks
Mancini, Marc, author
Thomson/Delmar Learning, 2005
Buku Teks