M. T. Audu, D. N. Mbaezue, and S. Dauda. “THE ENGINEERING CHARACTERISTICS OF BLACK COTTON SOIL TREATED WITH CORN STRAW ASH”. International Journal of Advance Engineering and Research Development (IJAERD), vol. 6, no. 10, Oct. 2019, pp. 74-80, https://ijaerd.org/index.php/IJAERD/article/view/4427.