@article{Ludwig13-2,
  title = {Perfekte Quadrate},
  author = {Matthias Ludwig},
  year = {2013},
  url = {http://www.springerprofessional.de/4244268.html},
  researchr = {https://researchr.org/publication/Ludwig13-2},
  cites = {0},
  citedby = {0},
  journal = {Wirtschaftsinformatik & Management},
  volume = {2013},
  number = {1},
  pages = {102-103},
}