@book { DasquivalenzprinzipinderAlterssicherung,
    title = "Das Äquivalenzprinzip in der Alterssicherung",
    author = "Jochen {Jagob}",
    year = "2004",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    doi = "10.3726/b13579",
    url = "https://www.peterlang.com/document/1068179"
}