Khan, M. A., and V. Lucia. “?TETRA CYCLIC HETEROAROMATIC SYSTEMS. PART-II. BENZIMIDAZO [1, 2-A] BENZIMIDAZOLES”. Biological Sciences - PJSIR, vol. 43, no. 3, June 2000, pp. 168-70, https://v2.pjsir.org/index.php/biological-sciences/article/view/2022.