Tarbuck, Edward J.
Maxwell Macmillan, 1993
Buku Teks
McGeary, David
McGraw-Hill, 2004
Buku Referensi
Carlson, Diane H.
McGraw-Hill , 2008
Buku Teks
Davidson, Jon P.
Prentice Hall, 1997
Buku Teks
Hamblin, W. Kenneth (William Kenneth), 1928-
Burgen Publishing, 1985
Buku Teks