| Number | Name | Date | Kind |
|---|---|---|---|
| 1673636 | Perry | Jun 1928 | |
| 3391414 | Gordon | Jul 1968 | |
| 3399407 | Olson | Sep 1968 | |
| 3965507 | Reiland | Jun 1976 | |
| 4057245 | Gordon | Nov 1977 | |
| 4215857 | Gordon | Aug 1980 | |
| 4245838 | Gordon | Jan 1981 |
| Entry |
|---|
| Two Pages of Sketches, Labelled "R-2 Pit", Prepared in 1974 at Facilitites of Assignee of Present Application. |