00264nam a2200109Ia 4500082002200000100001700022245006500039260002500104300001500129500000500144700000500149  a307.7207bC456.ED  aChang, C. W.  aExtension education for agricultural and rural developmentb  aBangkokbUNFAOc1963  axvi, 186p.  a  a