Fisher, Ronald C.
Scott, Foresman, 1988
Buku Teks
Campbell, W. J.
The Law Book, 1954
Buku Teks
Gelfand, M. David
West Publishing, 1986
Buku Teks
Carr, Robert K.
University of Oklahoma Press, 1937
Buku Teks
Hansen, Alvin Harvey, 1887-1975
George Allen and Unwin, 1944
Buku Teks