@book { TrainingundEntwicklungvonFhrungskrften,
    title = "Training und Entwicklung von Führungskräften",
    author = "Olivia {Söller}",
    year = "2015",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    url = "https://m.diplom.de/document/303251"
}