Tools for Verifying

Bibliothèque nationale de France 
Book and Serial Vendors for Africa and the Middle East 
Book and Serial Vendors for Asia and the Pacific 
The British Library 
CATNYP--Catalog of the New York Public Library 
Center for Research Libraries 
HOLLIS--Harvard OnLine Library Information System 
LibDex--Library Index 
Library of Congress 
Measuring Units Conversion Table
Melvyl--Catalog of the University of California Libraries 
National Geographic Map Machine 
OCLC--The Online Computer Library Center 
Roman Numeral Converter
UNESDOC/UNESBIB--bibliography of UNESCO documents and publications and Library collection 
Universal Currency Converter