Online Resources

Christie's
http://www.christies.com (Centripetal Chair)

Cowan's Auctions, Inc.
http://www.cowanauctions.com (Centripetal Chair)

Google Patent Search
http://www.google.com/patents (1849 U.S. Patent for Springs)

Post Road Gallery
http://www.postroadgallery.com/centipetal.html (Centripetal Chair)