000 00311nam a2200121Ia 4500
008 130225s9999 xx 000 0 und d
245 _aSoil conserving tillage systems for corn
260 _aWashington
_c1958
300 _a1-16 p.
440 _aUnited States Department of A
901 _a58022
942 _cB
_2udc
999 _c9942
_d9942