@inbook{NBERc1504,
 Crossref = "NBERatki67-1",
 title = "AGENCY RATINGS",
 author = "Thomas R. Atkinson",
 BookTitle = "Trends in Corporate Bond Quality",
 Publisher = "UMI",
 pages = "50-57",
 year = "1967",
 URL = "http://www.nber.org/chapters/c1504",
}
@book{NBERatki67-1,
 title = "Trends in Corporate Bond Quality",
 author = "Thomas R. Atkinson",
 institution = "National Bureau of Economic Research",
 type = "Book",
 publisher = "UMI",
 year = "1967",
 URL = "http://www.nber.org/books/atki67-1",
}