@article{undecidabilityofthelambekcalculuswitha,
  title = {Undecidability of the Lambek calculus with a relevant modality},
  author = {Max Kanovich and Stepan Kuznetsov and Andre Scedrov},
  year = {2016},
  eprint = {1601.06303},
  archivePrefix = {arXiv},
  url = {http://arxiv.org/abs/1601.06303v4},
}