@book { SprachtestsinderDiskussion,
    title = "Sprachtests in der Diskussion",
    author = "Ingrid {Kühn} and Marianne {Lehker} and Waltraud {Timmermann}",
    year = "2021",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    url = "https://www.peterlang.com/document/1100100"
}