author = { Krueger, Alan National Bureau of Economic Research Ashenfelter, Orley },

title = { Estimates of the Economic Return to Schooling from a New Sample of Twins },

publisher = {National Bureau of Economic Research},

year = {August 1992},

booktitle = {NBER working paper series ; no. w4143},

address = { Cambridge, Mass },

url = { http://slubdd.de/katalog?TN_libero_mab2 }