http://www.pircenter.org/en/news/6973-1224507
https://media.defense.gov/2018/Feb/02/2001872890/-1/-1/1/EXECUTIVE-SUMMARY-TRANSLATION-FRENCH.PDF
https://www.osw.waw.pl/sites/default/files/pw_69_pesco_ang_net.pdf
https://www.aicgs.org/publication/refugees-terrorism-and-a-failing-security-architecture/
http://www.ecfr.eu/article/commentary_germanys_defence_commitments_nothing_but_paper_tigers
http://www.ecfr.eu/page/-/Keeping_Europe_Safe_After_Brexit2.pdf
https://sipri.org/sites/default/files/2017-09/yb17-summary-eng.pdf
https://www.cesifo-group.de/DocDL/ifoDD_18-01_03-09_Ochsner.pdf
http://dip21.bundestag.de/dip21/btd/19/007/1900700.pdf
http://peaceandsecurityindex.org/wp-content/themes/peaceandsecurity/images/PSFG-report.pdf