Issued Patents 1989
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4818373 | Process for upgrading tar and bitumen | David B. Bartholic | 1989-04-04 |
| 4804459 | Process for upgrading tar sand bitumen | David B. Bartholic | 1989-02-14 |
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4818373 | Process for upgrading tar and bitumen | David B. Bartholic | 1989-04-04 |
| 4804459 | Process for upgrading tar sand bitumen | David B. Bartholic | 1989-02-14 |