@book { DerUrlaubsanspruchalssynallagmatischerEinheitsanspruch,
    title = "Der Urlaubsanspruch als synallagmatischer Einheitsanspruch",
    author = "Natascha {Ziemek}",
    year = "2016",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    doi = "10.3726/978-3-653-06253-3",
    url = "https://www.peterlang.com/document/1049843"
}