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).
Cross-reference note regarding further information on Tungsten contact points.
| Identifier | ExFiles\Box 35\6\ scan 437 | |
| Date | 31th December 1930 | |
| X.2894 31.12.30. For further matter relating to Tungsten contact points see X.6057. | ||