Teixeira, J. A.; Ribeiro, C.; Moreira, L. M.; Sousa, F. de; Pinho, A.; Graça, L.; Maia, J. C. Laparoscopic Cholecystectomy and Open Cholecystectomy in Acute Cholecystitis: Critical Analysis of 520 Cases. Acta Med Port 2014, 27, 685-691.