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)	Sonstiges	Scott	498 b
The Philatelic Foundation, (Prüferkommission)	Attest	Scott	5
Crowe, William T. (Sonstiges)	Attest	Scott	5
Weiss Expertizing International, . (Sonstiges)	Attest	Scott	5 A
The Philatelic Foundation, (Prüferkommission)	Attest	Scott	5 A
Weiss jr., William R. (Sonstiges)	Attest	Scott	5 A
Crowe, William T. (Sonstiges)	Attest	Scott	526