Judd, Dennis R., author
Little, Brown, 1979
Buku Teks
Sharkansky, Ira, author
McGraw-Hill, 1975
Buku Teks
Dolbeare, Kenneth M., author
D.C. Heath, 1985
Buku Teks
by James E. Anderson; David Brady; Charles Bullock III; Joseph stewart, JR
Brooks/Cole; cengage learning, 1984
Buku Teks
Rourke, Francis E., author
Little, Brown, 1979
Buku Teks