@inbook{NBERc9837,
 Crossref = "NBERaesm73-1",
 title = "A Generalized Approach to Estimation as Implemented in the Troll/I System",
 author = "Mark Eisner and Robert S. Pindyck",
 BookTitle = "Annals of Economic and Social Measurement, Volume 2, number 1",
 Publisher = "NBER",
 pages = "28-50",
 year = "1973",
 URL = "http://www.nber.org/chapters/c9837",
}
@book{NBERaesm73-1,
 title = "Annals of Economic and Social Measurement, Volume 2, number 1",
 author = "Sanford V. Berg, editor",
 institution = "National Bureau of Economic Research",
 type = "Book",
 publisher = "NBER",
 year = "1973",
 URL = "http://www.nber.org/books/aesm73-1",
}