@book { AllesberSchach,
    title = "Alles über Schach",
    subtitle = "Mythen. Kuriositäten. Superlative",
    author = "Michael {Ehn} and Hugo {Kastner}",
    year = "2010",
    publisher = "humboldt",
    address = "Hannover, Deutschland",
    url = "https://schluetersche.openpublishing.com/document/403381"
}