D. S. CHANDRIKA, K. L. SHARMA, S. VIDYAVATHI, MUNNALAL, T. S. KUMAR, and K. U. RANI, “Effect of conservation tillage, residue and nitrogen levels on soil nitrogen fractions and their contributions in nitrogen uptake in castor (Ricinus communis)”, Indian J Agri Sci, vol. 86, no. 4, pp. 474–80, Apr. 2016, doi: 10.56093/ijas.v86i4.57456.