From the Print Room showing a date stamp.
| Identifier | ExFiles\Box 14\8\ Scan307 | |
| Date | 30th May 1931 | |
| ROLLS-ROYCE, LIMITED PRINT ROOM, 30 MAY 31 | ||
From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).