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Antiqbook   Balogh Scientific Books
Buchantiquariat   Buchhaus Stern-Verlag Janssen
Camden Books   ebay
Koeltz Scientific Books   Midnight Special Bookstore
NVvA   Newport Book Store
PRB&M   Rutherford's Booksite
Scholars West   Zentrales Verzeichnis Antiquarischer  

ebay - Large Online Auction website. Simple registration required for bidding. Many categories in addition to books. (ebay search tips).
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NVvA, Nederlandsche Vereeniging van Antiquaren, The Dutch Antiquarian Booksellers' Association, founded in 1935 with the object of promoting reliability in the trade of old books and prints.
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ANTIQBOOK
antiquarian booksellers online   ANTIQBOOK, provided by NAN (The Netherlands Antiquarian Booksellers Network).
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Philadelphia Rare Books & Manuscripts Company: Early Printed Books, Substantive Manuscripts. U.S. & Latin America, Mexico & New World Languages, Hispanica, Histories & the History of Ideas, Travels, Law, Religion, & Bibles (all prior to 1820).
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