Elliott, Philip, author
Herder and Herder, 1972
Buku Teks
Richards, J.M.
Newton Abbot: Davis and Charles, 1974
Buku Teks
Celia, Michael A.
Prentice-Hall, 1992
Buku Teks
Rathbone, Robert R., author
Addison-Wesley Publishing Company, 1985
Buku Teks
Trzyna, Thomas N., author
Wadsworth, 1987
Buku Teks