@article{nmbr9asaconstraintprogrammingchallenge,
  title = {Nmbr9 as a Constraint Programming Challenge},
  author = {Mikael Zayenz Lagerkvist},
  year = {2020},
  eprint = {2001.04238},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2001.04238v1},
}