1. 2009
2. U.S. Environmental Protection Agency Office of Transportation and Air Quality. EPA and NHTSA Set Standards to Reduce Greenhouse Gases and Improve Fuel Economy for Model Years 2017-2025 Cars and Light Trucks 2012
3. Ministry of Environmental Protection of the People's Republic of China Limits and Measurement Methods for Emissions from Light-Duty Vehicles, 2013
4. Japanese Ministry of Economy Trade and Industry Act on the Rational Use of Energy 2013