BALMUKAND, B.H. Studies in crop variation-V- The r_elation between yields and soil nutrients. Journal of Agricultura! Sciences, (18): 602-27, 1928.

BARBER, S.A. The changing phylosophy of soil test interpretations in soil testing and plant analysis. Walsh e Beaton (ed.). Soil Science Soe. America, lnc., 1973.

BAUM, E.l.; HEADY, E.O.; BLACKMORE, J. (ed.). Methodological proeedures in the economic analysis of fertilizer use data. The Iowa State College Press, 1956.

BAUM, E.L.; HEADY, E.O.; PESEK, J.T.; HILDRETH, C.G. (ed.). Economic and technieal analysis of fertilizer innovations and resource use. The Iowa State College Press. 1957.

BRADY, N.C. The nature and properties of soils, 3th ed. McMillan, 1974.

BRAY, R.H. A nutrient mobility concept of soil-plant relationships. Soil Science. (78): 9- 23, 1954.

_ _ _ _ . Confirmation of the nutrient mobility concept of soil-plant relationships. Soil Science, 95 (2): 124-31, 1963.

____.Thecorrelationofaphosphorussoiltestwiththeresponseofwheatthougha modified Mitscherlich equation. Soil Sei. Soe. Amer. Proc., (22): 314-17, 1958.

CATE, R.B. & NELSON, LA. A simple statistical procedure for particing soil test correlation data in two classes. Soil Sei. Soe. Amer. Proc., (35): 858-60, 1971.

COREY, R.B. & SCHULTE, E.E. Factors affecting the availability of nutrients to plants - in soil testing and plant analysis. Walsh and Beaton (ed.). Soil Sei. Soe. Amer., lnc., 1973.

CROWTHER, E.W. & YATES, F. Fertilizer policy in wartime: fertilizer requirements of arable crops. Empire Jour. Exp. Agr. (IX): 77-97, 1941.

EPSTEIN, E. Mineral nutrition of plants: principies and perspectives. John Wiley, 1972

FULLER, W. Grafted polynomials as approximating functions. Aust. Jour. Agric. Econ., (13): 35-46, 1969.

HADLEY, G. Non linear and dynamic programming. Addison-Wesley, 1964.

HEADY, E.O. Methodological problems in fertilizer use. ln: Methodological procedures in the economic analysis of fertilizar use data. Baum, Heady e Blackmore (ed.). The Iowa State College Press, 1956.

HEADY, E.O. & DILLON, J. Agricultura! production functions. The Iowa State College Press, 1961.

HILDRETH, C.G. Discrete models with qualitative restrictions. ln: Methodological procedures in the economic analysis offertilizer use data. Baum, Heady e Blackmore (ed.). The Iowa State College Press, 1956.

JOHNSON, P. R. Alternative functions for analyzing a fertilizer-yield relationship. J. F.E., 35 (4): 519-29, 1953.

LANZER, E.A.; PARIS, O.; GREEN, R. A maximum likelihood estimator for switching regressions with common gaussian noise. Working Paper No. 78-8. Department of Agricultural Economics, University of California (Davis), 1978.

MADDALA, G.S. Econometrics. McGraw-Hill, 1977.

MALAVOLTA, E.; HAAG, H.P.; MELLO, F.A.F.; BRASIL S.0 , M.0.C. La nutricion mineral de algunas cosechas tropicales. lnst. lntern. de la Potasa, 1964.

MASON, D.D. Functional models and experimental designs for characterizing response curves and surfaces. ln: Methodological procedures in the economic analysis of fertilizer use data. Baum, Heady e Blackmore (ed.). The Iowa State College Press. 1956.

MUNSON, L.0. & DOLL, J.P. The economics of fertilizer use in crop pro_duction. Advances in Agronomy. v. XI. Academic Press, 1959.

PERRIN, R.K. The value of information and the value theoretical models in crop response research. AJAE, 58 (1): 54-61, 1976.

REDMAN, J .C. & ALLEN, S.0. lnterrelationships of economic and agronomic concepts. JFE, 36 (3): 453-65, 1954.

ROUSE, R.D. Soil test theory and calibration for cotton, corn, soybeans and coastal bermudagrass. Bulletin 375. Agric. Exp. Sta. Auburn University, Alabama, 1968.

RUSSEL, J. Soil conditions and plant growth, 1oth ed. Longmans, 1973.

RYAN, J. "A generalized crop fertilizer production function". Unpublished Ph.D. Dissertation. North Carolina State University (Raleigh), 1972.

TISDALE, S.L. & NELSON, W.L. Soil fertility and fertilizers. 7th ed. McMillan, 1971.

WALLACE, T.D. Pretest estimation in regression: a survey. AJAE, 59 (3): 431-43, 1977.