00290nam a2200109Ia 450000500170000000800410001705000150005810000200007324500420009326000330013565000120016820251229085628.0251229s9999    xx            000 0 und d  aQH 541 .B7  aBrewer, Richard 0aPrinciples of ecologycRichard Brewer  aLondonb W.B. Saundersc1979  aEcology