@book { AuslnderklauselnimProfisport,
    title = "Ausländerklauseln im Profisport",
    author = "Christian {Heidersdorf}",
    year = "1998",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    url = "https://www.peterlang.com/document/1086317"
}