1. American Wind Energy Association (Online).
http://www.awea.org/
2. Canada Wind Energy Association (Online).
http://www.canwea.ca/
3. European Wind Energy Association (Online).
http://www.ewea.org/
4. Electric Reliability Council of Texas (Online).
http://www.ercot.com/
5. Ackerman T (2005) Wind power in power systems. Wiley, New York