| Issuer | Date | Desc | State | ||
| - | no image | Bhutan | 2/15/1988 | empty sheet (#50735) | incomplete |
| - | no image | Bhutan | 2/15/1988 | empty sheet (#50736) | incomplete |
| - | no image | Bhutan | 3/31/1988 | empty sheet (#50737) | incomplete |
| - | no image | Bhutan | 3/31/1988 | empty sheet (#50738) | incomplete |
| - | no image | Bhutan | 3/31/1988 | empty sheet (#50739) | incomplete |
| - | no image | Bhutan | 3/31/1988 | empty sheet (#50740) | incomplete |