1. 20% Wind energy by 2030, increasing wind energy's contribution to U.S. electricity supply;U.S. Department of Energy;Energy Efficiency and Renewable Energy Tech. Rep. DOE/GO,2008
2. Asmus P. Seitzler M. The wind energy operations and maintenance report Wind Energy 2010
3. Designing Engineering Systems for Sustainability
4. The wind energy operations and maintenance report Wind Energy Update 2011