[1] C. W. Thornthwaite and J. R. Mather, “Average Climate Water Balance Data of the Continents. Part 1,” Africa Publication in Climatology, Vol.15, No. 2, 1962, pp. 68- 92.
[2] K. C. Short and A. J. Stauble, “Outline of Geology of Niger Delta,” Bulletin of American Association of Petroleum Geologist, Vol.57, No. 5, 1967, pp. 761-779.
[3] R. C. Ward, “Principles of Hydrology,” Mc-GrawHill, London, 1967, p. 216.
[4] J. S. Oguntoyinbo, “Heat and Water Balance Studies in Nigeria,” The Role of Hydrology and Hydrometeorology in the Economic Development of Africa, W.M.O., Vol. 301, No. 2, 1987, pp, 1-9.
[5] G. O. P. Obasi, “Water Balance in Nigeria,” Nigeria Metrological Service Quarterly Met. Magazine, Vol. 2 No. 2 1972, pp. 91-127.