@inbook{NBERc3135,
 Crossref = "NBERlong52-1",
 title = "Increase in Hours during World War II: United States",
 author = "Clarence D. Long",
 BookTitle = "The Labor Force in War and Transition: Four Countries",
 Publisher = "NBER",
 pages = "45-46",
 year = "1952",
 URL = "http://www.nber.org/chapters/c3135",
}
@book{NBERlong52-1,
 title = "The Labor Force in War and Transition: Four Countries",
 author = "Clarence D. Long",
 institution = "National Bureau of Economic Research",
 type = "Book",
 publisher = "NBER",
 year = "1952",
 URL = "http://www.nber.org/books/long52-1",
}