@book { DasEigenmittelsystemderEuropischenUnion,
    title = "Das Eigenmittelsystem der Europäischen Union",
    author = "Guido K. {Raddatz}",
    year = "2018",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    doi = "10.3726/b13729",
    url = "https://www.peterlang.com/document/1068309"
}