@article{DimitrovaKoppitz2020,
  author    = {Ilinka Dimitrova and J{\"o}rg Koppitz},
  title     = {On relative ranks of the semigroup of orientation-preserving transformations on infinite chains},
  journal   = {Asian-European journal of mathematics},
  volume    = {14},
  number    = {08},
  doi       = {10.1142/S1793557121501461},
  year      = {2020},
}