@book { DieBeistandsklauselimVertragvonLissabon,
    title = "Die Beistandsklausel im Vertrag von Lissabon",
    author = "Armin {Kockel}",
    year = "2012",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    doi = "10.3726/978-3-653-01430-3",
    url = "https://www.peterlang.com/document/1045948"
}