| Issuer | Date | Desc | State | ||
| - | no image | Bhutan | 2/27/1971 | empty sheet (#50625) | incomplete |
| - | no image | Bhutan | 2/27/1971 | empty sheet (#50626) | incomplete |
| - | no image | Bhutan | 4/15/1971 | empty sheet (#50627) | incomplete |
| - | no image | Bhutan | 11/30/1971 | empty sheet (#50628) | incomplete |