DOI:
https://dx.doi.org/10.18723/diw_ddc:2015-78
Frei zugängliche Version: (econstor)
http://hdl.handle.net/10419/110626
This paper is distributed under the terms of the Creative Commons Attribution 4.0 International License (CC-BY-4.0): https://creativecommons.org/licenses/by/4.0/