00299nam a2200109Ia 4500008004100000022001400041040001100055245004000066260006100106300001300167300000900180251112s9999||||xx |||||||||||||| ||und||  a0028-4793  aCNCLSA 4aThe New England Journal of Medicine  cJuly 1, 1999bThe Massachusetts Medical SocietyaEngland  aP. 1-708  bV.21