@book { ProfessionellesPosing,
    title = "Professionelles Posing",
    author = "Henrik {Pfeifer}",
    year = "2016",
    publisher = "Schlütersche Verlagsgesellschaft mbH & Co. KG",
    address = ", Deutschland",
    url = "https://schluetersche.openpublishing.com/document/404128"
}