How to cite Renewable Energy
Godfrey Boyle is one of the most quoted book in Renewable Energy, according to Google Scholar it reach 1208 quote. That is why his book is text book on Renewable Energy material.
The renewable ranges from technologies that are well established and mature to those that need further research and development (Hepbasli, 2008) #2
The yield, the tones of biomass produced per hectare per year, is a very important factor for energy crops. Yields depend on many factors; the location, climate and weather, the nature of the soil, supplies of water, nutrients, etc.…, and the choice of plant. Thus, yield implies extremely low conversion efficiency (Saidur, 2011) #23
A very good expression often recommended for modeling the behavior of wind speed is the Weibull pdf Formula (4). This recommendation is based on a comparison of actual wind speed profiles at different sites and wind speed profiles estimated using the Weibull pdf 
Boyle, Godfrey. Renewable energy. OXFORD university press, 2004.
Hepbasli, Arif. “A key review on exergetic analysis and assessment of renewable energy resources for a sustainable future.” Renewable and Sustainable Energy Reviews 12.3 (2008): 593-661.
Saidur, R., et al. “A review on biomass as a fuel for boilers.” Renewable and Sustainable Energy Reviews 15.5 (2011): 2262-2289.