@book { RckenohneSchmerz,
    title = "Rücken ohne Schmerz",
    author = "Ellen {Warstat} and Dr. Felix {Söller}",
    year = "2019",
    publisher = "humboldt",
    address = "Hannover, Deutschland",
    url = "https://schluetersche.openpublishing.com/document/451597"
}