A comparative cross-sectional study of psychological distress, fatigue, and physical activity in patients with rheumatoid arthritis, systemic lupus erythematosus, and Sjögren's disease - Beider, Sonja; Stephan, Michael; Seeliger, Tabea; Skripuletz, Thomas; Witte, Torsten; Ernst, Diana (Frontiers in Medicine, 2025)