Graham, Walter W.
Littlefield, Adams & Co., 1965
Buku Teks SO
Coaldrake, William Howard
Routledge, 1996
Buku Teks SO
Travers, Kenneth J.
Laidlaw Brothers, 1987
Buku Teks SO
Jurgensen, Ray C.
Houghton-Miffiln, 1983
Buku Teks SO
Brumfiel, Charles Francis, 1914-
Addison-Wesley, 1962
Buku Teks SO