Worldwide Experts
Comprehensive list of worldwide philatelic experts
Professional Stamp Experts
Specializes in United States stamps, leading firm for grading
The Philatelic Foundation
Non-profit, specializes in United States stamps and covers and grading.
American Philatelic Society
Largest stamp collector's organization in the United States
American Stamp Dealer's Association
Main governing body for members of the stamp industry
Linn's Stamp News
Weekly Stamp Publication
Royal Philatelic Society of London
Oldest philatelic society in the world
Smithsonian National Postal Museum
The British Library
Preeminent British resource
Philatelic Bibliopole
Philatelic literature
James E. Lee
Philatelic literature
Philip Bansner
Philatelic literature