Rugkhla, A. . “Effect of Pursley (Richardia scabra L.) on Growth, Nitrogen Uptake an dYield Loss in roselle (Hibsicus sabdariffa var. altissima)”. Thai Agricultural Research Journal, vol. 9, no. 3, Sept. 1991, pp. 162-6, https://li01.tci-thaijo.org/index.php/thaiagriculturalresearch/article/view/242391.