@article{zlotnik_2002, 
  title={On Superconvergence of a Gradient for Finite Element Methods for an Elliptic Equation with the Nonsmooth Right–hand Side}, 
  DOI={10.2478/cmam-2002-0018}, 
  publisher={Walter de Gruyter GmbH}, 
  author={Zlotnik}, 
  year={2002}
  }