References
- Republic of Kenya (1968 )Monthly motor vehicles registration report. Central Bureau of Statistics.
- Menden Hall , Ott and Sheaffer . 1971 . Elementary Survey Sampling , Wadsworth Publ. Co. Inc .
- Ongaya, G.T.E. (1968) Road Competition Survey (unpublished report).
- Som , R. K. 1973 . A Manual of Sampling Techniques , London : Heinemann .