1. EPA Renewable fuel standard program (RFS2) regulatory impact analysis http://www3.epa.gov/otaq/renewablefuels/420r10006.pdf
2. Kaempf D Advanced Energy Initiative http://georgewbush-whitehouse.archives.gov/stateoftheunion/2006/energy/energy_booklet.pdf
3. Energy Independence and Security Act One Hundred Tenth Congress of the United States 1 st Session, H.R. 6; 2007-01-12, Sections 201-251, Title II. Energy security through increased production of biofuels 2007 https://www.gpo.gov/fdsys/pkg/BILLS-110hr6enr/pdf/BILLS-110hr6enr.pdf