Lieberman, Marc, author
South Western Cengage Learning, 2013
Buku Teks
McKenzie, Richard B., author
McGraw-Hill, 1978
Buku Teks
Frieden, Jeffry A., author
Thomson Wadsworth, 2000
Buku Teks
Wicksteed, Philip Henry, 1844-1927, author
Augus M. Kelley, 1950
Buku Teks
edited by James H. Weaver
Allyn and Bacon, 1973
Buku Teks