Isaacs, Asher, 1902-1963, author
Dryden Press, 1952
Buku Teks
Harriss, C. Lowell (Clement Lowell), 1912-2009, author
Prentice-Hall, 1967
Buku Teks
Blumner, Sidney M., author
Kendall Hunt, 1971
Buku Teks
Massachusetts Addison-Wesley , 1950
Buku Teks
McKenna, John R.
Harper and Row , 1971
Buku Teks