@book { EinfhrungindieMikrokonomik,
    title = "Einführung in die Mikroökonomik",
    author = "Klaus {Herdzina} and Stephan {Seiter}",
    year = "2015",
    publisher = "Vahlen",
    address = "München, Deutschland",
    url = "https://vahlen.openpublishing.com/document/1221268"
}