edited by Ian Ousby
Cambridge University Press, 1993
Buku Referensi
edited by Ian Qusby
Cambridge University Press, 1988
Buku Referensi
Perrin, Porter G., author
Scott, Foresman, 1950
Buku Teks
Howard, Godfrey, author
Pan Macmillan Publishers, 1993
Buku Referensi
Whitla, William, author
Wiley-Blackwell, 2010
Buku Referensi