edited Steven L. Spiegel
St. Martin's Press, 1981
Buku Teks
Molloy, Bruce
University of Queensland Press, 1990
Buku Teks
Lincoln, W. Bruce
Chandler Publishing Company, 1968
Buku Teks
Smith, Page
McGraw-Hill, 1985
Buku Teks
Tuchman, Barbara W.
Macmillan, 1965
Buku Teks