editors, Tim Halliday, Kraig Adler, Christopher O'toole
Grolier International, 1993
Buku Referensi
Blum, Mark
Chronicle Books, 1999
Buku Referensi
"New York: Andromedia Oxford, 1994.",
Buku Teks
editors, Tim Halliday, Kraig Adler
Facts on File, 1994
Buku Referensi
Zug, George R.
Academic Press, 1993
Buku Teks