https://verfassungsblog.de/with-exclusive-competence-comes-great-responsibility/
https://verfassungsblog.de/the-rise-and-fall-of-world-constitutionalism/
http://library.fes.de/pdf-files/iez/13375.pdf
http://www.ecfr.eu/page/-/ECFR_215_GERMANY_VOTES_EUROPEAN_DILEMMAS_IN_THE_FEDERAL_ELECTION.pdf