Americana Exchange Rare Books - Worldwide book auction calendar and listings, and an extensive bibliographical database. Focus on Americana.
Bibliographic Research - Company offering evaluation and certification of old and rare books.
Odd Volumes United - Dealers can make dead stock pay. Collectors can find the dust jackets that make their modern firsts fully valuable. Researchers and libraries can acquire that needed missing periodical.
PK Books - Online Book Appraisals - Pricing service for rare and used books based on condition, ephemera values, estate collections, taxes and insurance purposes.