1. Nelson, V.: ‘Wind energy, renewable energy and the environment’, (CRC Press, London 2009)
2. Simos, M.G., and Ferret, F.A.: ‘Renewable energy systems’, (CRC, Orlando, Fl 2004)
3. Boldia, I.: ‘Variable speed generator, the electrical generator handbook’, (Taylor & Francis, CRC, New York 2006)
4. Operation of self-excited generators for windmill application