@book { FhrungimWandel,
    title = "Führung im Wandel",
    author = "Stefan {Käsler}",
    year = "2003",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783832463663",
    url = "https://m.diplom.de/document/221801"
}