00266nam a2200097Ia 450000500170000000800410001705000200005810000180007824500430009626000290013920251229191211.0251229s9999    xx            000 0 und d  aS 561 .B3 1979.  aBarnard, C.S. 0aFarm planing and control.cC.S Barnard  aLondonb Cambridgec1973