@book { DasPrinzipFortschritt,
    title = "Das Prinzip Fortschritt",
    subtitle = "Ein neues Verständnis für die Herausforderungen unserer Zeit",
    author = "Werner {Mittelstaedt}",
    year = "2008",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    url = "https://www.peterlang.com/document/1105081"
}