“?PRODUCTIVITY OF RICE-WHEAT SYSTEM IN RELATION TOAZOLLA GREEN MANURE FERTILIZED WITH NITROGEN AND PHOSPHORUS”. Biological Sciences - PJSIR 41, no. 1 (February 16, 1998): 32–35. Accessed April 25, 2026. http://www.v2.pjsir.org/index.php/biological-sciences/article/view/2226.