Tiwari, R.S., and Ram-Awatar. “Protoeusaccites Gen. Nov.- A Case of Transitionary, Character-State in Saccus Structure in the Late Permian Bisaccate Pollen”. Journal of Palaeosciences 42, no. 1-3 (December 31, 1993): 387–395. Accessed May 4, 2024. https://www.jpsonline.co.in/index.php/jop/article/view/1159.