Two more citations

 "What Is Biomass." ReEnergy Holdings. Web. 08 Mar. 2016.

-http://www.reenergyholdings.com/renewable-energy/what-is-biomass/ 

 Avila, Nelson. "Managing Municipal Wastes for Energy Generation in Nigeria." Renewable and Sustainable Energy Reviews. ScienceDirect. Web. 8 Mar. 2016.