Misra, Basant K., and B.D. Singh. “Liptinite Macerals in Singrauli Coals, India: Their Characterization and Assessment”. Journal of Palaeosciences 42, no. 1-3 (December 31, 1993): 1–13. Accessed May 4, 2024. https://www.jpsonline.co.in/index.php/jop/article/view/1128.