Arizona Historical Society                                     ---       https://arizonahistoricalsociety.org/ 

Postal History Foundation                                     ---       https://postalhistoryfoundation.org/  

Rocky Mountain Philatelic Library                        ---       https://rockymountainphilateliclibrary.org/

American Philatelic Society                                   ---       https://stamps.org/

American Association of Philatelic Exhibitors     ---      http://www.aape.org/

Arizona National Stamp Show                                 ---      https://arizonanationalstampshow.com/

Auxiliary Markings Club                                          ---      https://postal-markings.org/

Mobile Post Office Society                                      ---      https://www.eskimo.com/~wemmco/mposhome.html

Pacific NorthWest Postal History Society            ---     https://pacificnorthwestpostalhistorysociety.org/