Issued Patents 1989
Showing 1–4 of 4 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| D304574 | Charcoal fuel article | — | 1989-11-14 |
| 4834774 | Charcoal fuel article | Frederick J. Hrubecky, Doris A. Mills, Carl J. Gierke, Wilbert Heikkinen, Rory D. Williams +1 more | 1989-05-30 |
| 4810255 | Manufactured fuel article | Carl J. Gierke | 1989-03-07 |
| 4810256 | Composite fuel article | James Olszewski | 1989-03-07 |