1. Barker, J. 1984. Research perspectives on ageing: Black and Asian old people in Britain (1st ed.). London: Age Concern Research Unit.
2. Bhalla, A., and K. Blakemore. 1981. Elders of the minority ethnic groups. Birmingham: All Faiths for One Race.
3. Coady, A. 1992. Testimony: a philosophical study. Oxford: Clarendon Press.
4. Descartes, R. 1986. Meditations on first philosophy. Cambridge: Cambridge University Press.
5. Goldman, A.I. 1979. What is justified belief? In Justification and knowledge, ed. G. Pappas. Dordrecht: Reidel.