@unpublished{ClausDeckerKoschigetal.2015,
  author    = {Claus, Stephan and Decker, Eva and Koschig, Robert and Meier, Barbara},
  title     = {Mathe-{\"U}ben in Studium und Abitur},
  series    = {E-learning and Education Journal (eleed)},
  number    = {11},
  issn      = {1860-7470},
  url       = {https://eleed.campussource.de/archive/11/4131},
  institution = {Zentrale Einrichtungen},
  year      = {2015},
  language  = {de}
}