@techreport{NBERw13350,
 title = "Contracting for Government Services: Theory and Evidence from U.S. Cities",
 author = "Jonathan Levin and Steven Tadelis",
 institution = "National Bureau of Economic Research",
 type = "Working Paper",
 series = "Working Paper Series",
 number = "13350",
 year = "2007",
 month = "August",
 URL = "http://www.nber.org/papers/w13350",
}