Digital Transformation of Rheumatology Care in Germany: Cross-Sectional National Survey - Susann May; Robert Darkow; Johannes Knitza; Katharina Boy; Philipp Klemm; Martin Heinze; Nicolas Vuillerme; Pascal Petit; Patricia Steffens-Korbanka; Heike Kladny; Johannes Hornig; Peer Aries; et al. (Journal of Medical Internet Research)