Here are some useful links to other online resources. Please note the BTA is not responsible for any content on these websites.
Undertaking Research. Full-text guidance on philatelic research, courtesy of the Royal Philatelic Society, London. (Please note these are general guides applicable to all classes of philately).
David R Beech MBE FRPSL Philatelic Research - A Basic Guide
Charles Oppenheim FRPSL What Philatelists Need to Know About Copyright
Please note: these libraries are both closed during the coronavirus restrictions. Once reopened please check their websites for arrangements to visit.
Full Text Resources
Collecting Slogan Postmarks. 5 volumes covering 1917 - 1999. Courtesy of the Great Britain Philatelic Society
History of the Postcard Courtesy of Royal Mail
Special Event Postmarks of the United Kingdom. 5 volumes covering 1851 - 2013. Courtesy of the Great Britain Philatelic Society
Specialist Societies with themed interest
Sites of General Interest