@book { SystemtheoretischePerspektiven,
    title = "Systemtheoretische Perspektiven",
    author = "Karl {Edlinger} and Walter {Feigl} and Günther {Fleck}",
    year = "2021",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    url = "https://www.peterlang.com/document/1089428"
}