00313nam a2200097Ia 4500008004100000040001100041245008400052260005100136300001300187300001500200251112s9999||||xx |||||||||||||| ||und||  aCNCLSA 0aProceedings of the National Academy Of Sciences of the United States of America  cJune 1, 1999bBMJ Publishing Group LtdaLondon  aP. 1-682  bV. 140,141