@book { Forstkonomie,
    title = "Forstökonomie",
    author = "Volker {Bergen} and Wilhelm {Löwenstein} and Roland {Olschewski}",
    year = "2013",
    publisher = "Vahlen",
    address = "München, Deutschland",
    url = "https://vahlen.openpublishing.com/document/1220882"
}