July, Robert W
Charles Scribner's, 1970
Buku Teks
Standing, T. G.
Longmans, Green and Co., 1951
Buku Teks
Kennedy, Scott
Charles Scribner's , 1973
Buku Teks
Potter, Joan
Kensington Publishing, 2002
Buku Teks
Patton, Sharon F.
Oxford University Press, 1998
Buku Teks