edited by Steven Moorhead and Gordon Grice
Rockport Publisher, 1997
Buku Referensi
BooQs publisher data, 2010
Buku Referensi
Fleming, John
Penguin , 1999
Buku Referensi
edited by Simon Swaffield
University of Pennsylvania Press, 2002
Buku Teks SO
edited by Catherine Spellman
Actar, 2003
Buku Teks SO