@inbook{NBERc9517,
 Crossref = "NBERunkn38-2",
 title = "Program of Research",
 author = "NBER",
 BookTitle = "Report of the Committee on Prices in the Bituminous Coal Industry",
 Publisher = "NBER",
 pages = "29-76",
 year = "1938",
 URL = "http://www.nber.org/chapters/c9517",
}
@book{NBERunkn38-2,
 title = "Report of the Committee on Prices in the Bituminous Coal Industry",
 author = "NBER",
 institution = "National Bureau of Economic Research",
 type = "Book",
 publisher = "NBER",
 year = "1938",
 URL = "http://www.nber.org/books/unkn38-2",
}