Urkunden Prüfgebiet: USA (Unions-Ausgaben ab 1847)

Prüfer	Art des Attestes	Katalog	KatalogNr.
The Philatelic Foundation, (Prüferkommission)	Attest	Scott	491
PSE, Professional Stamp Experts (Prüferkommission)	Attest	Scott	491
PSE, Professional Stamp Experts (Prüferkommission)	Sonstiges	Scott	498 b
The Philatelic Foundation, (Prüferkommission)	Attest	Scott	5
Crowe, William T. (Sonstiges)	Attest	Scott	5
Weiss jr., William R. (Sonstiges)	Attest	Scott	5 A
The Philatelic Foundation, (Prüferkommission)	Attest	Scott	5 A
Weiss Expertizing International, . (Sonstiges)	Attest	Scott	5 A