@inbook{NBERc11956,
 Crossref = "NBERkess09-1",
 title = "Regulation (Agencies) versus Litigation (Courts): An Analytical Framework",
 author = "Richard A. Posner",
 BookTitle = "Regulation vs. Litigation: Perspectives from Economics and Law",
 Publisher = "University of Chicago Press",
 pages = "11-26",
 year = "2010",
 month = "December",
 URL = "http://www.nber.org/chapters/c11956",
}
@book{NBERkess09-1,
 title = "Regulation vs. Litigation: Perspectives from Economics and Law",
 author = "Daniel P. Kessler",
 institution = "National Bureau of Economic Research",
 type = "Book",
 publisher = "University of Chicago Press",
 year = "2011",
 URL = "http://www.nber.org/books/kess09-1",
}