@book { GrundfragenderWirtschaftspolitik,
    title = "Grundfragen der Wirtschaftspolitik",
    author = "Gerhard {Mussel} and Jürgen {Pätzold}",
    year = "2013",
    publisher = "Vahlen",
    address = "München, Deutschland",
    url = "https://vahlen.openpublishing.com/document/1219053"
}