1. D. G. Aronson & J. Serrin, Local behavior of solutions of quasilinear parabolic equations, Arch. Rational Mech. Anal. 25 (1967), pp. 81?123.
2. Chen Ya-Zhe & E. DiBenedetto, On the local behaviour of solutions of singular parabolic equations, Arch. Rational Mech. Anal. 103 (1988), pp. 319?345.
3. E. DeGiorgi, Sulla differenziabilità e l'analiticità delle estremali degli integrall multipli regolari, Mem. Acc. Sci. Torino, Cl. Se. Fis. Mat. Nat. 3 (3) (1957), pp. 25?43.
4. E. DiBenedetto, On the local behaviour of solutions of degenerate parabolic equations with measurable coefficients, Ann. Sc. Norm. Sup. Pisa Cp. Sc. Ser. IV, 8 (1986), pp. 487?535.
5. E. DiBenedetto, Topics in Quasilinear Degenerate and Singular Parabolic Equations, Lipschitz Lectures, Inst. Angew. Math., Bonn, Germany (1991).