APA (7th ed.) Citation

Udo, R. K. (1970). Geographical regions of Nigeria. University of California Press.

Chicago Style (17th ed.) Citation

Udo, Reuben K. Geographical Regions of Nigeria. Berkeley: University of California Press, 1970.

MLA (9th ed.) Citation

Udo, Reuben K. Geographical Regions of Nigeria. University of California Press, 1970.