by Frank B. Feigert ... [et al.] ; edited by Don C. Piper and Ronald J. Terchek
American Enterprise Institute for Public Policy Research, 1983
Buku Teks
Creighton, Donald
Macmillan, 1976
Buku Teks
edited by Robert W. Tucker, Charles B. Keely and Linda Wrigley
Westview Press, 1992
Buku Teks
McCormick, James M.
Thomson, 2005
Buku Teks
Herrick, Christopher
Longman, 2003
Buku Teks