Issued Patents 1989
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4820080 | Process for the construction of a drain system | Laszlo Varkonyi, Csaba Asszonyi | 1989-04-11 |
| 4804293 | Flexible layer structure for protecting earthworks, bed walls and for delimiting embedding layers | Laszlo Varkonyi | 1989-02-14 |