@book { DieLeihgabevonBerufssportlern,
    title = "Die Leihgabe von Berufssportlern",
    author = "Michael {Berkemeyer}",
    year = "2021",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    url = "https://www.peterlang.com/document/1107688"
}