@book { DerFirmentarifvertragalsFlexibilisierungsinstrument,
    title = "Der Firmentarifvertrag als Flexibilisierungsinstrument",
    author = "Oliver {Reinartz}",
    year = "2021",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    url = "https://www.peterlang.com/document/1103706"
}