Burton, Rosemary, author
Pitman, 1995
Buku Teks
Eastwood, John, author
Oxford University Press, 1994
Buku Teks
Wheeler, Geoffrey
Oxford University Press, 1962
Buku Teks
Sammons, Wheeler
A.W. Shaw Co. , 1915
Buku Teks
Wheeler, E. Todd
McGraw-Hill, 1964
Buku Teks