https://pubs.aeaweb.org/doi/pdfplus/10.1257/jep.34.2.172
https://ukandeu.ac.uk/explainers/the-ukraine-eu-relationship/?mc_cid=b812d9af50&mc_eid=815b1928ec
https://www.aspistrategist.org.au/germanys-weakness-is-bad-for-europe/
https://www.alter-eu.org/press-releases/2018/02/20-0