@book { DerfunktionelleAuftraggeberbegriffdes99GWB,
    title = "Der funktionelle Auftraggeberbegriff des § 99 GWB",
    author = "Martin Arndt {Peterle}",
    year = "2020",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    doi = "10.3726/b16714",
    url = "https://www.peterlang.com/document/1057416"
}