Optimal regularity for nonlinear elliptic equations with right-hand side measure in variable exponent spaces Sun-Sig ByunJung-Tae Park Indiana University Mathematics Journal 2018 text pdf 10.1512/iumj.2018.67.7517 10.1512/iumj.2018.67.7517 en Indiana Univ. Math. J. 67 (2018) 2133 - 2150 state-of-the-art mathematics http://iumj.org/access/