1. Poore , R. Lettenmaier , T. 2002 Alternative Design Study Report: WindPACT Advanced Wind Turbine Drive Train Designs Study, 1 November 2000-28 February 2002
2. Bywaters , G. John , V. Lynch , J. et al 2001 Northern Power Systems, Alternative Design Study Report, Period of Performance, 12 April 2001 to 31 January 2005
3. Jamieson , P.M. 2004 Evaluation of a GVT System for Wind Turbines