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).
The Phantom III Rocker gear, D.L. Series.
| Identifier | ExFiles\Box 96\2\ scan0311 | |
| Date | 18th August 1939 | |
| 354 Rm{William Robotham - Chief Engineer} Mx{John H Maddocks - Chief Proving Officer}/SB.{Mr Bull/Mr Bannister} 6/9. 18.8.39. P.III Rocker gear. D.L. Series. see file 1113. | ||