@book { Rollenspiele,
    title = "Rollenspiele",
    author = "Thomas {Erlach} and Burkhard {Sauerwald}",
    year = "2014",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    doi = "10.3726/978-3-653-04293-1",
    url = "https://www.peterlang.com/document/1048049"
}