Boston : D. Reidel Publishing
Majalah, Jurnal, Buletin
Edinburgh, Edinburgh University Press, 2005
Buku Referensi
Siobhan Chapman
Oxford University Press, 2005
Buku Teks
Oxford University Press , 1996
Buku Teks
Travis, Charles, author
Clarendon Press, 1989
Buku Teks