1. Annett, H. E.Memoir of the Department of Agriculture in India, Chemical Series, 1910,1, No. 9.
2. Harrison, W. H., and Ramaswamy Sivan, M. R.Ibid., 1912,2, No. 5.
3. Puri, A. N., and Lal, M.Punjab Irrigation Research Institute, Research Publication, 1938,4, No. 10.
4. Puri, A. N.Ibid., 1939,4, No. 12.