@inbook{NBERc12280,
 Crossref = "NBERannu40-1",
 title = "Part I, Report of the Director of Research",
 author = "Wesley C. Mitchell",
 BookTitle = "The National Bureau's Social Function",
 Publisher = "NBER",
 pages = "6-29",
 year = "1940",
 month = "March",
 URL = "http://www.nber.org/chapters/c12280",
}
@book{NBERannu40-1,
 title = "The National Bureau's Social Function",
 author = "NBER",
 institution = "National Bureau of Economic Research",
 type = "Book",
 publisher = "NBER",
 year = "1940",
 URL = "http://www.nber.org/books/annu40-1",
}