Kumaran, K.P. Navaneetha, and J.J. Edet. 1993. “Palynostratigraphy of the Late Cretaceous Nkporo Shale Outcrop in the Anambra Basin, Nigeria”. Journal of Palaeosciences 42 (1-3):372-79. https://doi.org/10.54991/jop.1993.1156.