@article{multioptionalmanysortedpastpresent,
  title = {Multi-optional Many-sorted Past Present Future structures and its description},
  author = {Sergio Miguel Tomé},
  year = {2018},
  eprint = {1801.08212},
  archivePrefix = {arXiv},
  url = {http://arxiv.org/abs/1801.08212v1},
}