Cooter, Robert
Scott, Foresman and company , 1988
Buku Teks
Barnes, David W., author
West Publishing , 1992
Buku Teks
edited by Sylvester E. Berki
Health, 1966
Buku Teks
Elzinga, Kenneth G., author
Yale University Press, 1976
Buku Teks
Posner, Richard A., author
Litle, Brown, 1980
Buku Teks