@misc{Frahm2013,
  author    = {Jan-Peter Frahm},
  title     = {Contents of amino acids and osmotic values of epiphytic lichens as indicators for regional atmospheric nitrogen loads},
  booktitle = {Archive for lichenology ; 9},
  issn      = {1868-4173},
  series    = {Archive for lichenology},
  number    = {9},
  type      = {workingpaper},
  pages     = {11},
  year        = {2013},
}