edited by Mary Feeney
Bowker Sour Limited, 1994
Buku Teks
Mader, Chris, author
Science Research Associates , 1974
Buku Teks
Nagoya University of Commerce and Business,
Majalah, Jurnal, Buletin
Artikel Jurnal
Terranova, Tiziana, author
Pluto Press, 2005
Buku Teks