@book { ManagingforHappiness,
    title = "Managing for Happiness",
    author = "Jurgen {Appelo} and Jürgen {Dittmar} and Mike {Leber} and Dirk {Schwammkrug}",
    year = "2018",
    publisher = "Vahlen",
    address = "München, Deutschland",
    url = "https://vahlen.openpublishing.com/document/1221021"
}