@book { FreelanceralsForschungsgegenstandundPraxisphnomen,
    title = "Freelancer als Forschungsgegenstand und Praxisphänomen",
    author = "Stephan {Kaiser} and Stefan {Süß} and Ingrid {Josephs}",
    year = "2021",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    url = "https://www.peterlang.com/document/1108289"
}