Harari, Maurice, author
Prentice-Hall, 1962
Buku Teks
edited by David E. Long and Bernard Reich
Westview Press, 1986
Buku Teks
Palmer, Monte, author
Thomson Wadsworth, 2007
Buku Teks
Bill, James A., author
Littel Brown and Company, 1984
Buku Teks
Henry, Clement M., 1937-, author
Cambridge University Press, 2010
Buku Teks