Patent Databases
inventored	http://www.inventored.org/patent-search/
Patent Database Comparison Table	http://www.lib.duke.edu/chem/patcomp.htm
Patent hunter	http://www.patentdatabase.com/
USPTO	http://www.uspto.gov/patft/index.html
World Intellectual Property Organization	http://www.wipo.org/
world patent	http://pctgazette.wipo.int/
US PTO	http://appft1.uspto.gov/netahtml/PTO/index.html
esp	https://worldwide.espacenet.com/?locale=en_EP
FreePatent online	http://www.freepatentsonline.com/6302913.html
WIPO	http://www.wipo.int/patentscope/search/en/search.jsf
PATENTSCOPE	http://www.wipo.int/pctdb/en/