@book { DASEINMALEINSDERBRSEFREINSTEIGER,
    title = "DAS EINMALEINS DER BÖRSE FÜR EINSTEIGER",
    author = "Marian {Sommer}",
    year = "2023",
    publisher = "via tolino media",
    address = "München, Deutschland",
    url = "https://tolino.openpublishing.com/document/1395190"
}