https://www.researchprojecttopics.com/2018/11/01/a-geophysical-investigation-using-seismic-refraction-method-to-determine-the-causes-of-road-failure-a-case-study-of-iruekpen-ozalla-road-axis-2/
A GEOPHYSICAL INVESTIGATION USING SEISMIC REFRACTION METHOD TO DETERMINE THE CAUSES OF ROAD FAILURE, A CASE STUDY OF IRUEKPEN-OZALLA ROAD AXIS