Hang, L., Shao, D. and Sun, W. 2011. The ED50and ED95 of ketamine for prevention of postoperative hyperalgesia after remifentanil-based anaesthesia in patients undergoing laparoscopic cholecystectomy. Swiss Medical Weekly. 141, 1920 (May 2011), w13195. DOI:https://doi.org/10.4414/smw.2011.13195.