Kulkarni, S. (1969) “Studies in the Glossopteris flora of India - 40. Sphnopteris polymorpha Feistm. (1881) emend. from the barakar stage of South Karanpura coalfield, Bihar, India”, Journal of Palaeosciences, 18(1-3), pp. 208–211. doi: 10.54991/jop.1969.836.