https://www.socialeurope.eu/2017/06/mercron-franco-german-tandem-back-berlins-terms/
https://www.realclearpolitics.com/articles/2022/11/08/avoiding_another_gettysburg_148442.html?utm_source=newsletter&utm_medium=email&utm_campaign=07%2F11%2F2022+++(Copy)
https://www.bruegel.org/system/files/2024-07/PB%2010%202024.pdf
https://dailynewshungary.com/mayors-of-v4-countries-capitals-sign-pact-of-free-cities/