| 1. |
stamps.org |
|
| 2. |
filatelia.fi |
|
| 3. |
usps.com |
|
| 4. |
uspcs.org |
|
| 5. |
pennypost.org |
|
| 6. |
essayproof.net |
|
| 7. |
westerncoversociety.com |
|
| 8. |
csalliance.org |
|
| 9. |
hawaiianstamps.com |
Hawaii Philately |
| 10. |
si.edu |
|
| 11. |
rossitertrust.com |
|
| 12. |
rpsl.org.uk |
|
| 13. |
paphs.org |
|
| 14. |
njpostalhistory.org |
|
| 15. |
siegelauctions.com |
|
| 16. |
jameslee.com |
James E. Lee |
| 17. |
veratrinder.org |
Vera Trinder |
| 18. |
vaccari.it |
Vaccari |
| 19. |
loc.gov |
|
| 20. |
coppoweb.com |
|
| 21. |
atms.ch |
|
| 22. |
princelystates.com |
|
| 23. |
blueyonder.co.uk |
|
| 24. |
mclstamps.co.uk |
|
| 25. |
chilecollector.com |
|
| 26. |
interpostalseals.com |
|
| 27. |
rmpldenver.org |
|
| 28. |
postalhistoryfoundation.org |
|
| 29. |
www.bl.uk |
|
| 30. |
posten.se |
Stockholm, Sweden |
| 31. |
stamplibrary.org |
|
|