@techreport{NBERw13246,
 title = "What Do Nonprofits Maximize? Nonprofit Hospital Service Provision and Market Ownership Mix",
 author = "Jill R. Horwitz and Austin Nichols",
 institution = "National Bureau of Economic Research",
 type = "Working Paper",
 series = "Working Paper Series",
 number = "13246",
 year = "2007",
 month = "July",
 URL = "http://www.nber.org/papers/w13246",
}