Makin, John H.
American Entreprise Institute, 1991
Buku Teks
Anderson, Thomas J., author
South- Western , 1958
Buku Teks
Vig, Norman J.
CQ Press, 1984
Buku Teks
Liston, Robert A., author
Dell Publishing, 1968
Buku Teks
Ross, Marc H.
McGraw-Hill, 1981
Buku Teks