@book { SynergieeffekteinderFremdsprachenforschung,
    title = "Synergieeffekte in der Fremdsprachenforschung",
    author = "Helmut J. {Vollmer}",
    year = "2021",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    url = "https://www.peterlang.com/document/1103160"
}