A low observed-to-expected postoperative mortality ratio in a Swiss high-standard peri-operative care environment – an observational study. Swiss Medical Weekly, [S. l.], v. 145, n. 4344, p. w14205, 2015. DOI: 10.4414/smw.2015.14205. Disponível em: https://www.smw.ch/index.php/smw/article/view/2083. Acesso em: 15 oct. 2025.