@misc{valle2018order,
  title={Order batching using an approximation for the distance travelled by pickers},
  author={Cristiano Arbex Valle and John E Beasley},
  year={2018},
  eprint={1808.00499},
  archivePrefix={arXiv},
  primaryClass={math.OC},
  url={https://arxiv.org/abs/1808.00499}
}