00313nam a2200109Ia 450000500170000000800410001708200160005810000220007424500590009626000400015530000080019520260224041021.0260224s9999||||xx |||||||||||||| ||und||  a630.717 SMI  aClarence B. Smith 4aThe agricultural extension system of the united states  aLondon: John Wiley & Sons Co.c1930  a402