@article{Litovsky91,
  title = {Free Submonoids and Minimal omega-Generators of R:::omega:::},
  author = {Igor Litovsky},
  year = {1991},
  url = {http://www.inf.u-szeged.hu/kutatas/actacybernetica/vol10n12/igor/igor.xml},
  researchr = {https://researchr.org/publication/Litovsky91},
  cites = {0},
  citedby = {0},
  journal = {Acta Cybern.},
  volume = {10},
  number = {1-2},
  pages = {35-44},
}