@article{etna_vol8_pp36-45,
  author  = {Manfred Dobrowolski and Steffen Gr\"af and Christoph Pflaum},
  title   = {On a posteriori error estimators in the finite element method on anisotropic meshes},
  journal = {Electron. Trans. Numer. Anal.},
  volume  = {8},
  year    = {1999},
  pages   = {36--45},
}