@book { DieDurchsetzungsRichtlinievom29April2004,
    title = "Die Durchsetzungs-Richtlinie vom 29. April 2004",
    author = "Susanne {Klein}",
    year = "2012",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    doi = "10.3726/978-3-653-01396-2",
    url = "https://www.peterlang.com/document/1045858"
}