Issued Patents 1997
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 5681170 | Electronic learning apparatus with self-adjusting level of difficulty | Frederick Rieber, Randolph J. Primozic, Jr. | 1997-10-28 |
| 5590876 | Ball tossing device | — | 1997-01-07 |