Issued Patents 1989
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4820582 | Waterproof photographic paper support | Heinz-Otto Merz, Alois-Bernhard Kerkhoff | 1989-04-11 |
| 4808267 | Waterproof photographic paper support | Alois-Bernhard Kerkhoff, Rudolf Wanka | 1989-02-28 |