1. Ackello-Ogutu, C., 1997. Unrecorded cross-border trade between Kenya and Uganda. Technical paper no. 59. Regional Trade Agenda Series. USAID/African Bureau, Washington, DC
2. African Development Bank, 1999. African Development Report 1999: Infrastructure Development in Africa. Oxford University Press, Oxford
3. The development of air transportation in Nigeria;Akpoghomeh;Journal of Transport Geography,1999
4. The road freight industry in Nigeria: new challenges in an era of structural adjustment;Alokan;Transport Reviews,1995
5. Barwell, I., 1996. Transport and the village: Findings from African village-level travel and transport surveys and related studies. World Bank discussion paper no. 344, Africa region series. The World Bank, Washington, DC