00319nam a2200085Ia 4500008004100000082001900041100002200060245006700082260008400149220204s9999    xx            000 0 und d  a632.95:33bBIR  aBirthal, Pratap S 0aEconomic potential of biological substitutes for agrochemicals  aNew DelhibNational Centre for Agricultural Economics nad Policy Researchc2003