@book { BesteuerungvonErtrgen,
    title = "Besteuerung von Erträgen",
    author = "Dietmar {Wellisch} and Jörg {Kroschel}",
    year = "2012",
    publisher = "Vahlen",
    address = "München, Deutschland",
    url = "https://vahlen.openpublishing.com/document/1220772"
}