Wicksteed, Philip Henry, 1844-1927, author
Augus M. Kelley, 1950
Buku Teks
Mill, John Stuart
Colonial Press, 1898
Buku Klasik
edited by James H. Weaver
Allyn and Bacon, 1973
Buku Teks
Bye, Raymond T.
Appleton-Century-Crofts, 1947
Buku Teks
Hedges, Burke
Inti Publishing, 1999
Buku Teks