Issued Patents All Time
Showing 1–1 of 1 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4193718 | Earth retaining wall of vertically stacked chevron shaped concrete blocks | York A. Wahrendorf, Herbert K. Frenzel, Knud Rasmussen, Horst Seibert, Horst J. Dieckmann | 1980-03-18 |