@book { DerCTestBeitrgeausderaktuellenForschungTheCTestContributionsfromCurrentResearch,
    title = "Der C-Test: Beiträge aus der aktuellen Forschung / The C-Test: Contributions from Current Research",
    author = "Rüdiger {Grotjahn}",
    year = "2021",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    url = "https://www.peterlang.com/document/1135532"
}