00537nam a2200133Ia 4500008004100000082002800041100002000069245005700089260004600146300001400192600003700206600001900243650014100262140224s9999    xx            000 0 und d  a330.19:631.675:519.2 L8  aHexem, Roger W.  aWater production functions for irrigated agriculture  aIowabIowa State University Presscc 1978  axvi,215p.  a Roger W.Hexem and Earl O.Heady.  aHeady, Earl O.  aIrrigated farming-economic aspects-Mathematical models,Irrigated farming-economic aspects-the west,Production functions(Economic theory)