Elkhebu, Ahmed Giuma, Adnan Zainorabidin, Huat B. K Bujang, Ismail Hj. Bakar, Lokman Abdeljouad Abdeljouad, and Wisam khalef Dheyab. 2019. “Alkaline Activation of Clayey Soil Using Potassium Hydroxide & Fly Ash”. International Journal of Integrated Engineering 10 (9). https://penerbit.uthm.edu.my/ojs/index.php/ijie/article/view/2477.