@inbook{NBERc11271,
 Crossref = "NBERbrad91-1",
 title = "Is the Gasoline Tax Regressive?",
 author = "James M. Poterba",
 BookTitle = "Tax Policy and the Economy, Volume 5",
 Publisher = "The MIT Press",
 pages = "145-164",
 year = "1991",
 month = "January",
 URL = "http://www.nber.org/chapters/c11271",
}
@book{NBERbrad91-1,
 title = "Tax Policy and the Economy, Volume 5",
 author = "David Bradford",
 institution = "National Bureau of Economic Research",
 type = "Book",
 publisher = "The MIT Press",
 year = "1991",
 URL = "http://www.nber.org/books/brad91-1",
}