@book { HandelnultraviresderEuropischenGemeinschaft,
    title = "Handeln «ultra vires» der Europäischen Gemeinschaft",
    author = "Jens U. {Flick}",
    year = "2021",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    url = "https://www.peterlang.com/document/1092386"
}