| Issuer | Date | Desc | State | ||
| - | no image | Bhutan | 5/20/1968 | empty sheet (#50601) | incomplete |
| - | no image | Bhutan | 5/20/1968 | empty sheet (#50602) | incomplete |
| - | no image | Bhutan | 7/8/1968 | empty sheet (#50603) | incomplete |
| - | no image | Bhutan | 7/8/1968 | empty sheet (#50604) | incomplete |
| - | no image | Bhutan | 7/8/1968 | empty sheet (#50605) | incomplete |
| - | no image | Bhutan | 7/8/1968 | empty sheet (#50606) | incomplete |