41
32. SPRAGUE, H. B. (Editor). Hunger singns in crops. A
symposium New York, McKay, 1964. 460 p.
33. SPRAGUE, G. F. Y LARSON, W. E. Producci6n de Ma'z.
Manual de Agricultura No. 322. M6xico, CRAT,
1972.
34. WAUGH, D L. et al. Discontinuos models for rapid
correlation interpretation, and utilization of soil analyses and fertilizer response data. Tech. Bull.
No. 7. North Carolina State Univ. International Soil Fertility Evaluation and Improvement
Project. August 1973. 77p.
Vo.Bo.
Palmira S. de Quan
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