World Intellectual Property Organization
http://www.wipo.org

United States Patent and Trademark Office
http://www.uspto.gov

European Patent Office
http://www.european-patent-office.org

Japan Patent Office
http://www.jpo.go.jp/

Office for Harmonization in the Internal Market
http://oami.eu.int/en/default.htm

Swiss Federal Institute of Intellectual Property
http://www.ige.ch/E/sitemap.htm