Horton, Paul B., author
Dow Jones Irwin, 1982
Buku Teks
Acuff, F. Gene, author
The Dryden Press, 1973
Buku Teks
Schrag, Clarence C., author
Harper & Row, 1963
Buku Teks
Zanden, James W. Vander, author
John Wiley & Sons, 1979
Buku Teks
Ogburn, William F., author
Houghton Mifflin, 1946
Buku Teks