| PSE, Professional Stamp Experts (Prüferkommission) |
Attest |
Scott |
C 15 |
| BPA, Expertising Limited (Prüferkommission) |
Attest |
Scott |
C 17; C 23 |
| The Philatelic Foundation, (Prüferkommission) |
Attest |
Scott |
C 19 |
| The Philatelic Foundation, (Prüferkommission) |
Attest |
Scott |
C 23 c |
| The Philatelic Foundation, (Prüferkommission) |
Attest |
Scott |
C 3 |
| Vincent Graves Greene, Philatelic Research Foundation (Prüferkommission) |
Attest |
Scott |
C 3 c |
| Colomphil, (Prüferkommission) |
Attest |
Scott |
C 37 |
| The Philatelic Foundation, (Prüferkommission) |
Attest |
Michel |
C 3b; c3 |
