https://www.boeckler.de/pdf/p_wsi_report_52_2019.pdf
https://www.diw.de/documents/publikationen/73/diw_01.c.670904.de/19-31-3.pdf
https://www.ifo.de/DocDL/EEAG-2019-executive-summary.pdf
https://www.tni.org/files/publication-downloads/marketforces-report-tni-statewatch.pdf