Christie's: The New York headquarters. Online catalogues.
Robert A. Siegel Auction Galleries, Inc.: Stamps, also sold retail. Online catalogues, prices realized lists.
Sotheby's: The New York branch of the international auction house.
Swann Galleries Auctioneers: Auctions of rare and antiguarian books, maps and atlases, autographs and manuscripts, photographs, prints and drawings, and vintage posters.
William Doyle Galleries: Arts auctions and appraisals. Online catalogues and sale results.