@inbook{NBERc2940,
 Crossref = "NBERunkn54-1",
 title = "Regional and National Product Projections and their Interrelations",
 author = "Walter Isard and Guy Freutel",
 BookTitle = "Long-Range Economic Projection",
 Publisher = "NBER",
 pages = "425-471",
 year = "1954",
 URL = "http://www.nber.org/chapters/c2940",
}
@book{NBERunkn54-1,
 title = "Long-Range Economic Projection",
 author = "Conference on Research in Income and Wealth",
 institution = "National Bureau of Economic Research",
 type = "Book",
 publisher = "NBER",
 year = "1954",
 URL = "http://www.nber.org/books/unkn54-1",
}