@inbook{NBERc10525,
 Crossref = "NBERaesm77-4",
 title = "Merging Microdata Rationale Practice and Testing",
 author = "Nancy Ruggles and Richard Ruggles and Edward N. Wolff",
 BookTitle = "Annals of Economic and Social Measurement, Volume 6, number 4",
 Publisher = "NBER",
 pages = "407-428",
 year = "1977",
 month = "October",
 URL = "http://www.nber.org/chapters/c10525",
}
@book{NBERaesm77-4,
 title = "Annals of Economic and Social Measurement, Volume 6, number 4",
 author = "Sanford V. Berg",
 institution = "National Bureau of Economic Research",
 type = "Book",
 publisher = "NBER",
 year = "1977",
 URL = "http://www.nber.org/books/aesm77-4",
}