An observational study of the timing of surgery, use of laparoscopy and outcomes for acute cholecystitis in the USA and UK - Murray, AC; Markar, S; Mackenzie, H; Baser, O; Wiggins, T; Askari, A; Hanna, G; Faiz, O; Mayer, E; Bicknell, C; Darzi, A; Kiran, RP (Surgical Endoscopy, 2018)