@misc{ 0-306655969, title = {Working papers / National Bureau of Economic Research, Inc}, address = {Cambridge, Mass.}, publisher = {[Verlag nicht ermittelbar]}, year = {1973}, issn = {1058-8450}, language = {English}, url = {http://www.bibliothek.uni-regensburg.de/ezeit/?1500086}, url = {http://www.nber.org/papers}, url = {https://www.ssrn.com/index.cfm/en/nber/}, url = {https://dbis.ur.de/frontdoor.php?titel_id=9453}, url = {https://dbis.ur.de/frontdoor.php?titel_id=100238}, url = {https://katalog.ub.tu-freiberg.de/Record/0-306655969} }