Chukwu Onu, and Ozioma Nwachukwu. “A Study on the Characteristics of Coal Fly Ash Collected from Southern U.S.A”. Global Journals of Research in Engineering, vol. 22, no. E1, July 2022, pp. 1-8, https://engineeringresearch.org/index.php/GJRE/article/view/101191.