TY - JOUR AU - Brusselaers, N; Lagergren, J TI - The Charlson comorbidity index in registry-based research JO - Methods Inf Med IS - 05 VL - 56 PY - 2017 DO - 10.3414/ME17-01-0051 L3 - PubMed-ID: 29582935 SP - 401 EP - 406 ER -