@book { TheaterinderZirkuskuppel,
    title = "Theater in der Zirkuskuppel",
    author = "Ernst-Marcus {Thomas}",
    year = "2003",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783832466473",
    url = "https://m.diplom.de/document/222034"
}