1. Paul HN, Radnor JP (1976) Highway Engineering. John Willey and Sons, New York
2. Oglesby CH, Garry HR (1978) Highway Engineering, 4th edn. John Willey and sons, New York, p 691
3. Kadyali LR, Lal NB (2008) Highway Engineering. Khanna Publishers Delhi-6, Fifth Edition, 858pp.
4. Olofinyo OO, Fatoyinbo OOF, IO, (2019) Engineering properties of residual soilsin part of Southwestern Nigeria: implication for road foundation. SN Appl. Sci. 1:507. https://doi.org/10.1007/s42452-019-0515-3
5. Gupta BL, Gupta A (2003) Roads, railways, bridges, tunnel and harbor dock engineering, 5th edn. Standard Publishers Distributors, NaiSarak, New Delhi