@book { DieEuropischeBrgerinitiativenachArt11Abs4EUV,
    title = "Die Europäische Bürgerinitiative nach Art. 11 Abs. 4 EUV",
    author = "Heiko {Piesbergen}",
    year = "2011",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    doi = "10.3726/978-3-653-00597-4",
    url = "https://www.peterlang.com/document/1044592"
}