3[3]Patrica Lanvand, Hommes,Marc De Kock.PractiCal guidelines on the postoperative use of patient-controlled analgesia in the elderly.Drugs Againg,1998,13:9-16.
4[4]Myster T,Jenson FG.The effect of posture on late postoperative hypoxaemia.Anaesthesia,1996,5l:225.