@inbook{NBERc3626,
 Crossref = "NBERbeck74-1",
 title = "The Optimum Enforcement of Laws",
 author = "George J. Stigler",
 BookTitle = "Essays in the Economics of Crime and Punishment",
 Publisher = "UMI",
 pages = "55-67",
 year = "1974",
 URL = "http://www.nber.org/chapters/c3626",
}
@book{NBERbeck74-1,
 title = "Essays in the Economics of Crime and Punishment",
 author = "Gary S. Becker",
 institution = "National Bureau of Economic Research",
 type = "Book",
 publisher = "UMI",
 year = "1974",
 URL = "http://www.nber.org/books/beck74-1",
}