Antiquarian Booksellers Associations	America Antiquarian Booksellers' Association of America Belgium Belgische Beroepskamer van Antiquaren The Netherlands Nederlandsche Vereeniging van Antiquaren
Book search engines Mega search engines	The Netherlands Antiqbook Boekwinkeltjes Germany ZVAB -- Austria Eurobuch America AddAll BookFinder
	The Netherlands Koninklijke Bibliotheek - KB Belgium Universiteitsbibliotheek Antwerpen Belgium, Antwerp Museum Plantin-Moretus America Google Yahoo
Libraries
Museums
Various search engines