4Johnso JE.Effects of accurate expectations about sensations on the secsary and distress components of pain[J].J Personality and Social Phychology,1973,27(1):26.
5Liu S,Carpenter RL,Neal JM,et al.Epidural anesthesia and analgesia:their role in postoperative outcome[J].Anesthesiology,1995,82(10):1488.