1. IEA. Annual Energy Outlook 2010, May 11, (2010).
2. IEO. The international Energy Outlook 2010 (IEO2010), July 27, (2010).
3. Hans T. Aichlmayr: Design Considerations, Modeling and Analysis of Micro-Homogenous Charge Compression, PhD thesis, University of Minnesota, Minnesota, USA, (2002).
4. Gregory Flynn: Some Principles and Applications of the Free-Piston Ignition Combustion Free-Piston Engine, General Motors Engineering Journals. p. 22-27 (1958).
5. London AL, Antoni K. Oppenheim: The Free-Piston Engine Development-Present Status and Design Aspects. Trans ASME, Vol. 74, p.1349-1361(1952).