00296nam a2200097Ia 4500008004100000082002400041100002200065245008000087260001500167300001600182260227b        |||||||| |||| 00| 0 eng d  a338.160973bR982.RE  aRuttan, Vernon W.  aResearch on the economic of technological change in American agricultureb/  c1960a b   app1019-1030