by Lawrence W. Scott [and others]
Burgess, 1976
Buku Teks
Tsaioun, Katya, editor
John Wiley & Sons, 2011
eBooks
McLeod, John, author
McGraw-hill Open University press, 2012
Buku Teks
Companion, Audrey L.
McGraw-Hill, 1979
Buku Teks
Hansen, David A.
Marcel Dekker, Inc, 1996
Buku Teks