00327nam a2200109Ia 4500008004100000040003800041100002100079245002600100260004800126300001700174653002600191220107s9999    xx            000 0 und d  cJayakar Knowledge Resource Centre  aTribe, Michael A 0aEcological principles  bCambridge University PressaCambridgec1975  aviii,161p p.  aEcological principles