@techreport{NBERt0262,
 title = "Treatment Effects for Discrete Outcomes when Responses to Treatment Vary Among Observationally Identical Persons: An Application to Norwegian ...",
 author = "Arild Aakvik and James J. Heckman and Edward J. Vytlacil",
 institution = "National Bureau of Economic Research",
 type = "Working Paper",
 series = "Technical Working Paper Series",
 number = "262",
 year = "2000",
 month = "September",
 URL = "http://www.nber.org/papers/t0262",
}