Below are links to various resources that may be of benefit to the collector. Please note that a link listed here does not necessarily imply endorsement by the SDAG. Also, please be aware that links sometime change.
Organizations and Specialty Societies
British North America Philatelic Society
British West Indies Study Circle
Ebony Society of Philatelic Events and Reflections
France and Colonies Philatelic Society
The Royal Philatelic Society London
U.S. Philatelic Classics Society
Expertizers and Expertizing Committees
APEX (American Philatelic Society)
British Philatelic Association (BPA) Expertising Ltd.
Confederate Stamp Alliance Authentication Service
The Vincent Graves Greene Philatelic Research Foundation
International Society for Japanese Philately
Philatelic Stamp Authentication and Stamp Grading, Inc (PSAG)