1. ISO14040:2006E Environmental Management—Life Cycle Assessment—Principles and Framework;International Organization for Standardization,2006
2. Renewable Fuel Standard Program (RFS2) Regulatory Impact Analysis [Internet];Assessment and Standards Division, Office of Transportation and Air Quality, US Environmental Protection Agency,2010
3. Directive 2009/28/EC of the European Parliament and of the Council of 23 April 2009 on the Promotion of the Use of Energy from Renewable Sources and Amending and Subsequently Repealing Directives 2001/77/EC and 2003/30/EC, OJ L 140/16,2009
4. A survey of unresolved problems in life cycle assessment;Reap;Int J Life Cycle Assess,2008