@inbook{NBERc5001,
 Crossref = "NBERleve25-1",
 title = "Index",
 author = "Maurice Leven",
 BookTitle = "Income in the Various States: Its Sources and Distribution, 1919, 1920, and 1921",
 Publisher = "NBER",
 pages = "303-308",
 year = "1925",
 URL = "http://www.nber.org/chapters/c5001",
}
@book{NBERleve25-1,
 title = "Income in the Various States: Its Sources and Distribution, 1919, 1920, and 1921",
 author = "Maurice Leven",
 institution = "National Bureau of Economic Research",
 type = "Book",
 publisher = "NBER",
 year = "1925",
 URL = "http://www.nber.org/books/leve25-1",
}