Brown, Ray Andrews, author
Callaghan & Company, 1955
Buku Teks
Lawson, F.H., author
Clarendon Press, 1958
Buku Teks
Boyer, Ralph E., author
St. Paul Minn, 1991
Buku Teks
Moynihan, Cornelius J., author
West Publishing, 1962
Buku Teks
World Intelectual Property Organization, 1989
Buku Teks