000 00297nam a2200121Ia 4500
008 191031s9999 xx 000 0 und d
100 _aEarl. O.Heady
245 0 _aAgricultural production functions
260 _bJowa State university press
260 _c1966
365 _b53.20
942 _cBK
999 _c196143
_d196143