@book { FreiHandeln,
    title = "Frei Handeln?",
    author = "Stephan {Pühringer}",
    year = "2011",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    doi = "10.3726/978-3-653-00914-9",
    url = "https://www.peterlang.com/document/1045803"
}