Newman, Daniel
Routledge, 2007
Buku Referensi
Lane, Edward William
Frederick Ungar Publishing, 1956
Buku Referensi
Jones, Daniel
Cambridge University Press, 2003
Buku Teks
Downes, Colm
Cambridge university press, 2009
Buku Teks
Ceramella, Nick
Cambridge university press, 2011
Buku Teks