@TechReport{economics.dp.2009-34,
 author = {Büttner, Thomas , Jacobebbinghaus, Peter , and Ludsteck, Johannes},
 title = {Occupational Upgrading and the Business Cycle in West Germany},
 type = {Economics Discussion Paper},
 institution = {Kiel Institute for the World Economy},
 year = {2009},
 number = {2009-34},
 url = {http://www.economics-ejournal.org/economics/discussionpapers/2009-34}
}