1. Abramowitz, M., Stegun, I.A.: Handbook of Mathematical Functions. Dover Publications Inc., New York, 1992
2. Adams, R.A.: Sobolev Spaces. Academic Press, New York, 1975
3. Angenent, S.B.: Large time asymptotics for the porous medium equation. In: Nonlinear diffusion equations and their equilibrium states I, volume 12 of Math. Sci. Res. Inst. Publ., Springer, New York, 1988, pp. 21?34
4. Bakry, D., Emery, M.: Diffusions hypercontractives. In: Sém. Proba. XIX, number 1123 in Lecture Notes in Math., Springer, New York, 1985, pp. 177?206
5. Barenblatt, G.I.: On some unsteady motions of a liquid or gas in a porous medium. Akad. Nauk. SSSR. Prikl. Mat. Mekh. 16, 67?78 (1952)