Butler, Henry N.
South-Western Publishing, 1987
Buku Teks
Watson, Donald Stevenson
Houghton Miffiln, 1960
Buku Teks
Manley, John F.
Macmillan, 1976
Buku Teks
Cranston, Ross
Oxford University Press, 1987
Buku Teks
Wood, Donna J.
Pitman , 1986
Buku Teks