Higher integrability of minimizers of degenerate functionals in carnot-caratheodory spaces

In this paper, we prove a higher integrability result for the horizontal gradient of a minimizer of a functional of the type whose matrix of the coefficients A(x) = tA(x) satisfies the anisotropic bounds where the ellipticity function K(x) ∈ A2 ∩RHτ, τ opportunely related to the homogeneous dimension, and is such that the pair