1. Barton, L. and MacNab, J., Effect of antibiotics on plant. Contr. Boyce Thompson Inst.17, 419 (1954).
2. Brian, P. W., The production of antibiotics by soil microorganisms. Chem. and Ind.1949, 391 (1949).
3. Brian, P. W. and Grove, J. F., Gibberellic acid. Endeavour16, 161 (1957).
4. Clark, F. E., Effects of soil amendments upon the bacterial populations associated with roots of wheat. Trans. Kansas Acad. Sci.42, 91 (1939).
5. Clark, F. E., and Thom, C., The effect of organic amendments upon the microflora of the rhizosphere of cotton and wheat. Trans. Third Comm. Int. Soc. Soil Sci.A, 94 (1939).