@inbook{NBERc10853,
 Crossref = "NBERpote01-1",
 title = "The Middle-Class Parent Penalty: Child Benefits in the U.S. Tax Code",
 author = "David T. Ellwood and Jeffrey B. Liebman",
 BookTitle = "Tax Policy and the Economy, Volume 15",
 Publisher = "MIT Press",
 pages = "1-40",
 year = "2001",
 month = "January",
 URL = "http://www.nber.org/chapters/c10853",
}
@book{NBERpote01-1,
 title = "Tax Policy and the Economy, Volume 15",
 author = "James M. Poterba",
 institution = "National Bureau of Economic Research",
 type = "Book",
 publisher = "MIT Press",
 year = "2001",
 URL = "http://www.nber.org/books/pote01-1",
}