@inbook{NBERc4252,
 Crossref = "NBERunkn69-3",
 title = "Front Matter to "New Challenges for Economic Research"",
 author = "",
 BookTitle = "New Challenges for Economic Research",
 Publisher = "NBER",
 pages = "-11--1",
 year = "1969",
 URL = "http://www.nber.org/chapters/c4252",
}
@book{NBERunkn69-3,
 title = "New Challenges for Economic Research",
 author = "NBER",
 institution = "National Bureau of Economic Research",
 type = "Book",
 publisher = "NBER",
 year = "1969",
 URL = "http://www.nber.org/books/unkn69-3",
}