* Erich Hau, "Wind turbines: fundamentals, technologies, application, economics " Springer, 2013 ISBN 978-3-642-27150-2 (preview on Google Books)* Siegfried Heier, "Grid integration of wind energy conversion systems" Wiley 2006, ISBN 978-0-470-86899-7.
* Erich Hau, "Wind turbines: fundamentals, technologies, application, economics " Springer, 2013 ISBN 978-3-642-27150-2 (preview on Google Books)* Siegfried Heier, "Grid integration of wind energy conversion systems" Wiley 2006, ISBN 978-0-470-86899-7.