1. Aigner, M., & Ziegler, G. M. (1998). Proofs from The Book. New York: SpringerVerlag.
2. Arber, A. (1954). The mind and the eye. Cambridge: Cambridge University Press.
3. Borba, M. C., & Skovsmose, O. (1997). The ideology of certainty in mathematics education. For the Learning of Mathematics, 17(3), 17–23.
4. Davis, P. J. (1995). The rise, fall, and possible transfiguration of triangle geometry. American Mathematical Monthly, 102(3), 204–214.
5. Davis, P. J., & Hersh, R. (1983). The mathematical experience. Harmondsworth: Penguin Books.