@techreport{NBERw12894,
 title = "Cementing Relationships: Vertical Integration, Foreclosure, Productivity, and Prices",
 author = "Ali Hortacsu and Chad Syverson",
 institution = "National Bureau of Economic Research",
 type = "Working Paper",
 series = "Working Paper Series",
 number = "12894",
 year = "2007",
 month = "February",
 URL = "http://www.nber.org/papers/w12894",
}