Smith, Hedrick
Ballantine Books, 1988
Buku Teks
Kraft, Joseph
The New American Library, 1966
Buku Teks
Dolbeare, Kenneth M., author
D.C. Heath, 1985
Buku Teks
Cater, Douglass
Vintage Books, 1964
Buku Teks
Fritschler, A Lee
Mass Ballinger Publishing , 1987
Buku Teks