edited by James Piscatori
Westview Press, 1987
Buku Teks
Palmer, Monte, author
Thomson Wadsworth, 2007
Buku Teks
Bill, James A., author
Littel Brown and Company, 1984
Buku Teks
Bill, James A., author
Little, Brown, 1979
Buku Teks
Harari, Maurice, author
Prentice-Hall, 1962
Buku Teks