00440    a2200145   4500082001700000100002200017245004400039260003800083300002000121650004100141650001300182650003000195650004400225700002500269  a631.372bJOH  aJohnson, Elmer J.  aServicing and maintaining farm tractors  aNew YorkbMcGraw-Hillc1950g1950  axvi,313p.c23cm  aAgriculture and related technologies  aTractors  aPower and power machinery  aTools, machinery, apparatus, equipments  aHollenberg, Alvin H.