@inbook{NBERc6797,
 Crossref = "NBERpote08-2",
 title = "Portfolio Substitution and the Revenue Cost of the Federal Income Tax Exemption for State and Local Government Bonds",
 author = "James M. Poterba and Arturo Ramírez Verdugo",
 BookTitle = "Economic Analysis of Tax Expenditures",
 Publisher = "National Tax Journal, (National Tax Association), Vol. 64, no. 2, part 2",
 year = "2011",
 month = "June",
 URL = "http://www.nber.org/chapters/c6797",
}
@book{NBERpote08-2,
 title = "Economic Analysis of Tax Expenditures",
 author = "James M. Poterba",
 institution = "National Bureau of Economic Research",
 type = "Book",
 publisher = "National Tax Journal, (National Tax Association), Vol. 64, no. 2, part 2",
 year = "2011",
 URL = "http://www.nber.org/books/pote08-2",
}