1. American Petroleum Institute, 2007a. Gasoline Taxes. 〈http://www.api.org/statistics/fueltaxes/upload/March_2007_gasoline_and_diesel_summary_pages-2.pdf〉.
2. American Petroleum Institute, 2007b. Notes to State Motor Fuel Excise and Other Tax Rates. 〈http://www.api.org/policy/tax/stateexcise/upload/March_2007_Notes.pdf〉.
3. CBS News, February 14, 2005. States Mull Taxing Drivers By Mile. CBSNews.com.
4. Incidence of federal and state gasoline taxes;Chouinard;Economics Letters,2003
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