World Intelectual Property Organization, 1989
Buku Teks
Colston, Catherine, author
Cavendish Publishing, 1999
Buku Teks
edited by A. James Casner
Little, Brown, 1952
Buku Teks
Lang, Jon, author
Sweet & Maxwell, 2006
Buku Teks
Cunningham, Roger A., author
West Pub., 1993
Buku Teks