@inbook{NBERc1968,
 Crossref = "NBERunkn67-1",
 title = "Studies New And Completed And Conferences On Research",
 author = "Various",
 BookTitle = "Contributions to Economic Knowledge Through Research",
 Publisher = "NBER",
 pages = "23-30",
 year = "1967",
 URL = "http://www.nber.org/chapters/c1968",
}
@book{NBERunkn67-1,
 title = "Contributions to Economic Knowledge Through Research",
 author = "NBER",
 institution = "National Bureau of Economic Research",
 type = "Book",
 publisher = "NBER",
 year = "1967",
 URL = "http://www.nber.org/books/unkn67-1",
}