Henry, Clement M., 1937-, author
Cambridge University Press, 2010
Buku Teks
Palmer, Monte, author
Thomson Wadsworth, 2007
Buku Teks
Harari, Maurice, author
Prentice-Hall, 1962
Buku Teks
Bill, James A., author
Littel Brown and Company, 1984
Buku Teks
edited by James Piscatori
Westview Press, 1987
Buku Teks