Johson, Bruce, author
Oxford University Press, 1987
Buku Teks
Wilde, William H., author
Oxford University Press, 1994
Buku Referensi
by Peter Dennis, Jeffrey Grey, Ewan Morris, Robin Prior
Oxford University Press, 1995
Buku Referensi
Lees, Stella, author
Oxford University Press, 1993
Buku Referensi
Walker, David M.
Clarendon Press, 1980
Buku Teks