@article{Mueller2008,
  author    = {Heribert M{\"u}ller},
  title     = {Heribert von K{\"o}ln (um 970 - 1021)},
  journal   = {Rheinische Lebensbilder},
  volume    = {8},
  pages     = {7 -- 20},
  year      = {2008},
}