00268nam a22001097a 450000500170000000800410001704000130005808200180007124500420008926000190013130000080015020180716102637.0180716b        xxu||||| |||| 00| 0 eng d  cPK-LaUMT  aMJC 050bLIF-  aLife : the backfround of segregation/  a[ ]b[ ]c1956  a[ ]