sent by Antea Galić Novaković

 for her cover Antea put souvenir sheet issued in 2021 to celebrate the 140th anniversary of diplomatic relations with U.S.A.

sent by ROTA Giancarlo

 

Borislav Atyashkin

 

sent by Gloria VIDAL BENITES

 

sent by Henrik LUNDGREN

 

sent by Park Choonjong

 

sent by Petri HAAPALA

 

sent by Pierre MILLIEN

 

sent by Jahfer.p.a

 

sent by Evelyn E. Mosher

 

sent by George ILIE

 

sent by Frank THIELE

 

sent by Pierre MILLIEN

 

sent by Serge Sadko

 

sent by Frank Thiele

 souvenir sheet on cover was issued for Stamp Day - it shows The Alexandria Blue Boy

The Alexandria "Blue Boy" is a rare Postmasters' Provisionals stamp produced in Alexandria, Virginia (then part of the District of Columbia) in 1847. There are seven known examples of Alexandria provisionals, however, the Blue Boy is the only specimen printed on blue paper. The other six are printed on buff paper. The Blue Boy remains affixed to its original envelope, and sold for $1.18 million in 2019, which is among the highest known prices paid for a philatelic item.

information found on website "wikiwand"