Cowen, Zelman
Oxford University Press, 1959
Buku Teks
Wright, Charles Alan
West Publishing, [1983, ]
Buku Referensi
Stephan, Paul B.
Emmanuel Law Outlines, 1994
Buku Teks
Williamson, J. Peter (John Peter)
Scott, Foresman, 1968
Buku Teks
edited by Erica l. Dolgin and Thomas G.P. Guilbert
West Publishing, 1997
Buku Teks SO