@book { DiegroeSchachschule,
    title = "Die große Schachschule",
    author = "Jonathan {Carlstedt}",
    year = "2017",
    publisher = "Schlütersche Verlagsgesellschaft mbH & Co. KG",
    address = ", Deutschland",
    url = "https://schluetersche.openpublishing.com/document/404142"
}