author = { Kremer, Michael National Bureau of Economic Research Olken, Benjamin A. },

title = { A Biological Model of Unions },

publisher = {National Bureau of Economic Research},

year = {April 2001},

booktitle = {NBER working paper series ; no. w8257},

address = { Cambridge, Mass },

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