Weishar, Peter, author
McGraw-Hill, 1998
Buku Teks
Mantovani, Giuseppe
Taylor and Francis, 1996
Buku Teks
editors, Alfred Beerli
Amacom, 2003
Buku Teks
Bertol, Daniela, author
John Wiley & Sons, 1997
Buku Teks
Kovacs, Diane K.
Facet Publishing, 2007
Buku Referensi