Issuer | Date | Desc | State | ||
- | no image | Poland | 1973 | empty sheet (#86334) | incomplete |
- | no image | Poland | 1973 | empty sheet (#86335) | incomplete |
- | Poland | 6/20/1973 | space-based observatories, sheet of 1 type | all added | |
- | Poland | 6/20/1973 | space-based observatories, sheet of 1 type | all added | |
- | Poland | 8/19/1973 | empty sheet (#8828) | incomplete | |
- | Poland | 8/19/1973 | empty sheet (#8829) | incomplete |