edited by Agosto
Rockport, 1998
Buku Teks
Edited by Agosto
Rockport publisher, 1998
Buku Referensi
New York Dava Kan 1998,
Buku Referensi
Peterson, Chris, author
Rockport Publishers, 1998
Buku Teks
Rasiel, Ethan M., author
McGraw-Hill, 2001
Buku Teks