| Issuer | Date | Desc | State | ||
| - | no image | Cambodia | 2/15/1991 | empty sheet (#28423) | incomplete |
| - | |
Cambodia | 3/30/1991 | empty sheet (#28424) | incomplete |
| - | |
Cambodia | 4/25/1991 | empty sheet (#28425) | incomplete |
| - | no image | Cambodia | 7/10/1991 | empty sheet (#28426) | incomplete |
| - | no image | Cambodia | 10/12/1991 | empty sheet (#28427) | incomplete |
| - | |
Cambodia | 11/16/1991 | empty sheet (#28428) | incomplete |