Sjodin,Terri L., author
Elex Media Komputindo, 2007
Buku Teks
Miller, William, author
American Management Association, 2009
eBooks
Humphries, john
Groiler International, 1993
Buku Teks
Rotondo, Jennifer, author
McGraw-Hill, 2002
Buku Teks
Remley, Jim, author
American Management Association, 2007
eBooks