M.L. GUPTA and R.N. SINGH, RAKESH PANDEY, S. KUMAR,. “Root-Knot Disease on Opium Poppy - A New Disease Record”. Indian Phytopathology, vol. 52, no. 1, June 2002, pp. 100-2, https://epubs.icar.org.in/index.php/IPPJ/article/view/19472.