P. Baroni, T. Kuusi, G. Mingione:
Borderline gradient continuity of minima
J. Fixed Point Theory Appl Vol. 15, N. 2, p. 537-575, 2014

P. Baroni, M. Colombo, G. Mingione:
Harnack inequalities for double phase functionals
Nonlinear Analysis Vol. 121, p. 206-222, 2015

P. Baroni, M. Colombo, G. Mingione:
Non-autonomous functionals, borderline cases and related function classes
St. Petersburg Math. J. Vol. 27, N. 3, p. 347-379, 2016

P. Baroni, M. Colombo, G. Mingione:
Regularity for general functionals with double phase
Calc. Var. Partial Differ. Equ. 2018

L. Beck, G. Mingione:
Optimal Lipschitz criteria and local estimates for non-uniformly
  elliptic problems
(preprint) 2018