@incollection{BockRoth2016,
  author    = {Wolfgang Bock and Andreas Roth},
  title     = {Der unm{\"o}gliche Freistoß},
  booktitle = {Neue Materialien fiir einen realit{\"a}tsbezogenen Mathematikunterricht 3},
  editor    = {Martin Bracke and Hans Humenberger},
  year      = {2016},
  url  = {http://nbn-resolving.de/urn:nbn:de:hbz:386-kluedo-43376},
}