Roberts, Ian
Oxrord University Press, 2007
Buku Teks
Gorrell, Paul. author
Cambridge University Press, 2006
Buku Teks
Baker, C.L.
MIT Press, 1989
Buku Teks
Schusky, Ernest l.
Prentice-Hall, 1973
Buku Teks
Gordon Wills ... [and others]
Pan Books, 1975
Buku Teks