@article{escidoc:0814,
  title = {{Theory of crystal field states for heavy rare-earth impurities in MgB2}},
  journal = {{Journal of Physics-Condensed Matter}},
  volume = {14},
  number = {43},
  pages = {10273--10279},
  year = {2002},
  author = {Welsch, F. and Kremer, R. and F\"ahnle, M.}
}