@article{undecidabilityofthelambekcalculuswith,
  title = {Undecidability of the Lambek calculus with subexponential and bracket modalities},
  author = {Max Kanovich and Stepan Kuznetsov and Andre Scedrov},
  year = {2016},
  eprint = {1608.04020},
  archivePrefix = {arXiv},
  url = {http://arxiv.org/abs/1608.04020v2},
}