https://www.researchprojecttopics.com/2018/07/06/a-geophysical-investigation-using-seismic-refraction-method-to-determine-the-causes-of-road-failure-a-case-study-of-iruekpen-ozalla-road-axis/
A Geophysical Investigation Using Seismic Refraction Method To Determine The Causes Of Road Failure, A Case Study Of Iruekpen-Ozalla Road Axis