@book { RckertskleineGelenkschule, title = "Rückerts kleine Gelenkschule", subtitle = "Die besten Expertentipps für gesunde Gelenke", author = "Uwe {Rückert}", year = "2019", publisher = "humboldt", address = "Hannover, Deutschland", url = "https://schluetersche.openpublishing.com/document/475340" }