@techreport{NBERw13016,
 title = "The Productivity Argument for Investing in Young Children",
 author = "James J. Heckman and Dimitriy V. Masterov",
 institution = "National Bureau of Economic Research",
 type = "Working Paper",
 series = "Working Paper Series",
 number = "13016",
 year = "2007",
 month = "April",
 URL = "http://www.nber.org/papers/w13016",
}