Saez, Eileen Elliott de
Facet Pub, 2002
Buku Teks
edited by David Baker and Wendy Evans
Emerald, 2017
eBooks
Hoffman, K. Douglas
Cengage Learning, 2017
Buku Teks
Hoffamn, K. Douglas
Horcourt Colledge Publisher, 2002
Buku Teks
Cornish, Graham P.
Facet Publishing , 2004
Buku Referensi