Tiwari, R.S., and Ram-Awatar. 1993. “Protoeusaccites Gen. Nov.- A Case of Transitionary, Character-State in Saccus Structure in the Late Permian Bisaccate Pollen”. Journal of Palaeosciences 42 (1-3):387-95. https://doi.org/10.54991/jop.1993.1159.