1. Bould, C., Bradfield, E. G. and Clarke, G. M. 1960 Leaf analysis as a guide to the nutrition of fruit crops. I. General principles, sampling techniques and analytical methods. J. Sci. Food Agric.11, 229–242.
2. Finney, D. J. 1971 Probit analysis 3rd Ed. Published by Cambridge University Press.
3. McCollum, J. P. and Skok, J. 1960 Radiocarbon studies on the translocation of organic constituents into ripening tomato fruits. Proc. Am. Soc. Hortic. Sci.75, 611–616.
4. Messing, J. H. L. and Winsor, G. W. 1956 Boron in the nutrition of tomato plants. Rept. Glasshouse Crops Research Inst.1956, pp 77–83.
5. O'Neill, J. V. and Webb, R. A. 1970 Simutaneous determination of nitrogen, phosphorus and potassium in plant material by automatic methods. J. Sci. Food Agric.21, 217–219.