Issued Patents All Time
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4686475 | Passive geophysical prospection system based upon the detection of the vertical electric field component of telluric currents and method therefor | H. David Procter-Gregg | 1987-08-11 |
| D287342 | Passive geophysical exploration device | H. David Procter-Gregg | 1986-12-23 |