Royal Philatelic Society of Canada (R.P.S.C.) – www.rpsc.org
Grand River Philatelic Association (G.R.V.P.A.) – www.grvpa.com
American Philatelic Society (A.P.S.) – www.stamps.org
APS Manual of Philatelic Judging and Exhibiting – http://www.stamps.org/Manual-and-Scoresheets
Barrie District Stamp Club – web site blocked, awaiting update.
Stamp World – https://www.stampworld.com/en/
Home Advisor, stamp collecting tips – https://www.homeadvisor.com/r/home-stamp-collecting-tips
The Origin and History of Post Cards – https://www.nextdayflyers.com/origin-and-history-of-postcards.html