Riesz and Wolff potentials and elliptic equations in variable exponent   weak Lebesgue spaces
  We prove optimal integrability results for solutions of the $p(\cdot)$-Laplace equation in the scale of (weak) Lebesgue spaces. To obtain this, we show that variable exponent Riesz and Wolff potentials maps $L^1$ to variable exponent weak Lebesgue spaces. 
Alexandre Almeida, Petteri Harjulehto, Peter H\"ast\"o and Teemu   Lukkari
math.FA math.AP