@article{DimitrovaKoppitz2011,
  author    = {Ilinka Dimitrova and J{\"o}rg Koppitz},
  title     = {On the maximal regular subsemigroups of ideals of order-preserving or order-reversing transformations},
  journal   = {Semigroup forum},
  volume    = {82},
  number    = {1},
  pages     = {172 -- 180},
  doi       = {10.1007/s00233-010-9272-8},
  year      = {2011},
}