Gaps in public health surveillance of elective surgery: a national analysis of inpatient data, COVID-19 impact, and coding validity in Germany (2006-2023). - Jacobi M; Roßlenbroich S; Roßlenbroich J; Kueckelhaus M; Giebeler N; Hirsch T; Rakhorst H; Wellenbrock S (Frontiers in public health, 2026)