Aron R. Halberstam Philatelists, Ltd. - Offers superb British Commonwealth stamps from 1890 to 1960. Comprehensive search and shopping cart. - http://www.arhstamps.com
GBStamps.com Links - Links for collectors of Great Britain stamps. - http://www.gbstamps.com/links.html#links_top
The One Penny and Twopence Postage Stamps of Great Britain - Brief outline of the major characteristics of the Penny Black and Twopence Stamps of Great Britain with plate study and information. - http://home.earthlink.net/~pennyred/
King George VI Great Britain - Stamps and Postal History of Great Britain from the reign of King George VI. - http://www.kg6gb.org
Early issues of Great Britain - Early issues of Great Britain with detailed study on hand punched check letters and stars in the upper corners. - http://www.kernunnos.com/Philately/GBQVLE.html