@inbook{NBERc9943,
 Crossref = "NBERaesm73-4",
 title = "The Applicabilty of the Kaiman Filter in the Determination of Systematic Parameter Variation",
 author = "David A. Belsley",
 BookTitle = "Annals of Economic and Social Measurement, Volume 2, number 4",
 Publisher = "NBER",
 pages = "527-530",
 year = "1973",
 month = "October",
 URL = "http://www.nber.org/chapters/c9943",
}
@book{NBERaesm73-4,
 title = "Annals of Economic and Social Measurement, Volume 2, number 4",
 author = "Sanford V. Berg, editor",
 institution = "National Bureau of Economic Research",
 type = "Book",
 publisher = "NBER",
 year = "1973",
 URL = "http://www.nber.org/books/aesm73-4",
}