Adebayo, B, and JM Akande. “Textural Properties Of Rock For Penetration Rate Prediction”. Daffodil International University Journal of Science and Technology 6, no. 1 (December 23, 2011): 1–8. Accessed May 6, 2024. https://www.banglajol.info/index.php/DIUJST/article/view/9327.