@book { EUGrundrechteundUmsatzsteuer,
    title = "EU-Grundrechte und Umsatzsteuer",
    author = "Markus {Müller}",
    year = "2021",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    doi = "10.3726/b18610",
    url = "https://www.peterlang.com/document/1063424"
}