Navy Department Bureau of Steam Engineering (1919). Notes on Liberty engine ignition system. Washington, D. C.: Government Printing Office. pp. 8, 20. Retrieved August 27, 2015.
Froom, Phil (2015). Evasion and Escape Devices: Produced by MI9, MIS-X and SOE in World War II. Schiffer Publishing. p. 228. ISBN9780764348396. OCLC1061720454.