University of Toronto Press, 1966
Buku Teks
Foster, John
Oxford University, 1969
Buku Teks
Symons, Julian, author
Arthur Barker, 1951
Buku Teks
Fielding, K.J., author
Longman, Green, 1953
Buku Teks
Mee, Jon, author
Cambridge University Press , 2010
Buku Teks