1. U.S. Department of Energy Alternative Fuels and Advanced Vehicles Data Center: ‘Hybrid electric vehicle incentives and laws’. Available:http://www.afdc.energy.gov/fuels/laws/3270/US
2. Department for Transport U.K.Ultra‐Low Carbon Cars: Next Steps on Delivering the £250 Million Consumer Incentive Program for Electric and Plug‐in Hybrid Cars 2009. Available:http://design.open.ac.uk/documents/DfTUltralowcarboncarsdelivery.pdf