00321nam a2200109Ia 450000500170000000800410001702000150005805000210007310000160009424500720011026000290018220251229191142.0251229s9999    xx            000 0 und d  a9022009467  aS 494.5 .A47U64   aUngar, E.D. 0aManagement of agropastoral systems in a semiarid region.cE.D Ungar  aPudocb Wageningenc1990