@book { DienstleistungsbetriebSchule,
    title = "Dienstleistungsbetrieb Schule",
    author = "Volker {Dörfler}",
    year = "2021",
    publisher = "Meidenbauer",
    address = ", Germany",
    url = "https://www.peterlang.com/document/1104124"
}