1. Adeleye AO (2005) Geotechnical investigation of sub-grade soil along sections of Ibadan-Ife highway unpublished M.Sc. project, Obafemi Awolowo University, Ile-Ife, p 181
2. Adenika CI (2016) Geophysical investigation of the failed-portions of 58–61 km of Ibadan-Ife road, Southwestern Nigeria (Unpublished M.Sc. Thesis), Department of Physics, Obafemi Awolowo University, Ile-Ife
3. Aigbedion I (2007) Geophysical investigation of road failure using electromagnetic profiles along Opoji, Uwenlenbo and Illeh in Ekpoma-Nigeria. Middle East J Sci Res 2(3–4):111–115
4. Ajayi LA (1987) Thought on road failure in Nigeria. Niger Eng 22(1):10–17
5. Balogun OY (2000) Senior secondary atlas, 2nd edn. Longman Nigeria Plc, Lagos Nigeria