1. P.P. Walsh, P. Fletcher, Gas Turbine Performance, Second ed., Blackwell Publishing, Malden, 2004, p. 38
2. M. Bellis, Turboshaft engines, Different types of engines, URL: 〈inventors.about.com/od/jstartinventions/ss/jet_engine_4.htm〉 [cited 28 June 2012].
3. Rotorcraft flying handbook, U.S. Department of Transportation, Federal Aviation Administration, Chapter 5–2, 2000.
4. D. Dilba, Pioneering new core engine technologies, MTU Aero Engines, MTU Aero Engines Holding AG., URL: 〈www.mtu.de/en/takeoff/report/archive_old/2_2010/210_newac/index.html〉 [cited 6 September 2012].
5. M.D. Paramour, M.J. Sapsard, Future technology and requirements for helicopter engines, in: W.A. Stewart (Ed.), NATO-AGARD Conference on Helicopter Propulsion Systems, Toulouse, France, 11–14 May 1981, AGARD-CP-302.