00398    a2200145   4500020001500000082001500015100002200030245005300052260004200105300002400147650002300171650002900194650001200223700001700235  a8123900422  a577.6bJEF  aJeffries, Michael  aFreshwater ecology bprinciples and applications  aNew DelhibCBS publishersc1990g1992  aix,285p.billc23cm  aFreshwater ecology  aLife sciences    Biology  aEcology  aMills, Derek