@book { GntherBeelitz,
    title = "Günther Beelitz",
    subtitle = "Die Jahre seiner Intendanz in Düsseldorf",
    author = "Claudia {Wagner}",
    year = "2004",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    url = "https://www.peterlang.com/document/1096369"
}