@book{Berger2008,
author = {Berger, Helge and Ehrmann, Michael and Fratzscher, Marcel},
year = {2008},
isbn = {3-938369-82-5},
language = {eng},
copyright = {http://www.fu-berlin.de/sites/refubium/rechtliches/Nutzungsbedingungen},
title = {Geography or skills?},
url = "http://dx.doi.org/10.17169/FUDOCS_document_000000002816",
}