Posthumus, Cyril (1977) [1977]. The Story of Veteran & Vintage Cars. John Wood, illustrator. Feltham, Middlesex, UK: Hamlyn. p. 115. ISBN0600391558. «This new unit gave notably better performance, delivering the customary Derby 'sufficiency' of silent horsepower via a new unit 4-speed gearbox and a hypoid bevel final drive.»
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Wood, Jonathan (2003) [1987]. The Rolls-Royce. Shire Album Series 198 (2nd edición). Princes Risborough, Buckinghamshire, UK: Shire Publications. p. 12. ISBN9780747805779. Consultado el 29 de marzo de 2012.
«Phantom II». Rolls-Royce Owners' Club. Mechanicsburg PA USA: Rolls-Royce Owners' Club. 2011. Archivado desde el original el 2 de abril de 2012. Consultado el 1 de abril de 2012. «The separate gearbox torque-tube drive and cantilever rear springing gave way to the PII's integral engine-gearbox unit, Hotchkiss drive, hypoid-bevel rear axle and semi-elliptic rear springs.»
«Phantom II». Rolls-Royce Owners' Club. Mechanicsburg PA USA: Rolls-Royce Owners' Club. 2011. Archivado desde el original el 2 de abril de 2012. Consultado el 1 de abril de 2012. «The separate gearbox torque-tube drive and cantilever rear springing gave way to the PII's integral engine-gearbox unit, Hotchkiss drive, hypoid-bevel rear axle and semi-elliptic rear springs.»