@article{DimitrovaKoppitz2022,
  author    = {Ilinka Dimitrova and J{\"o}rg Koppitz},
  title     = {On relative ranks of the semigroup of orientation-preserving transformations on infinite chain with restricted range},
  journal   = {Communications in algebra},
  volume    = {50},
  number    = {5},
  pages     = {2157 -- 2168},
  doi       = {10.1080/00927872.2021.2000998},
  year      = {2022},
}