We develop methods aimed at deriving regularity results for solutions to nonlinear degenerate parabolic equations and systems via local perturbation; as a consequence we obtain, in a unified way, Lipschitz continuity of solutions under weak parabolicity assumptions, and gradient continuity results in borderline cases. Nonlinear Schauder estimates as those of Misawa (2002)  are recovered and extended to more general settings. © 2012 Elsevier Masson SAS.
Kuusi, T., & Mingione, G. (2012). New perturbation methods for nonlinear parabolic problems. Journal Des Mathematiques Pures et Appliquees, 98(4), 390–427. https://doi.org/10.1016/j.matpur.2012.02.004