@book { DieKeinmannGmbH,
    title = "Die Keinmann-GmbH",
    subtitle = "Ein unmögliches Rechtsgebilde?",
    author = "Dirk {Oldenburg}",
    year = "1985",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    url = "https://www.peterlang.com/document/1074678"
}