1. Brencheley, W. E., Maskell, E. J. and Warrington, K., The inter-relations between silicon and other elements in plant nutrition. Appl. Biol.14, 45–82 (1927).
2. Butkwitsch, W. S., and Butkwitsch, W. W., Zur Frage nach der Rolle des ‘Donnanschen Membrangleichgewichts’ bei osmotischen Vorgangen in lebenden Zellen. Biochem.161, 468–487 (1925).
3. Hoagland, D. R., Davis, A. R. and Hibbard, P. L., The influence of one ion on the accumation of another by plant cells with special reference to experiments with Nitella. Plant Physiol.3, 473–486 (1928).
4. Islam, A., The yield and chemical composition of soybeans as affected by three levels of complementary nutrients associated with five levels of phosphorus. Pakistan J. Soil Sci.1, 32–47 (1964).
5. Mitsui, S. and Takatoh, H., Nutritional study of silicon in graminaceous crops. Soil Sci. Plant. Nutrition (Japan)9, 49–58 (1963).