ZEI Discussion Papers no. 269-272

Links
- https://www.zei.uni-bonn.de/de/ueber-zei/news/zei-discussion-papers/pic_dp269-272_874px.jpg/image_view_fullscreen
- https://www.zei.uni-bonn.de/de/ueber-zei/news/zei-discussion-papers/pic_dp269-272_874px.jpg/@@download/image/pic_dp269-272_874px.jpg