1. Global Wind Energy Council (GWEC). Global wind power continues expansion. Press release, Brussels 4 March 2005 http://www.ewea.org/documents/0304-Global%20Wind%20Energy%20Markets%20-%20FINAL.pdf.
2. Weis-Taylor P. Implementing agreement for co-operation in the research and development of wind turbine systems. International Energy Agency, IEA Wind Energy annual report 2003 http://www.ieawind.org/annual_reports.html.
3. European Wind Energy Association (EWEA), Press release, London 23 November 2004. http://www.bwea.com/media/news/record2004.html.
4. Quaschning V. Understanding renewable energy systems. London: Earth scan; 2005 [Chapters 5 and ].
5. Natural resources Canada RETScreen international. Clean Energy Decision Support Centre http://www.retscreen.net.