@inbook{NBERc9937,
 Crossref = "NBERaesm73-4",
 title = "Systematic (Non-Random) Variation Models: Varying Parameter Regression: A Theory And Some Applications",
 author = "Thomas F. Cooley and Edward C. Prescott",
 BookTitle = "Annals of Economic and Social Measurement, Volume 2, number 4",
 Publisher = "NBER",
 pages = "462-472",
 year = "1973",
 month = "October",
 URL = "http://www.nber.org/chapters/c9937",
}
@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",
}