@article{KoppitzSupaporn2013,
  author    = {J{\"o}rg Koppitz and Worakrit Supaporn},
  title     = {Categary equivalences of clones of operations preserving unaryoperations},
  journal   = {COMPTES RENDUS DE L ACADEMIE BULGARE DES SCIENCES},
  volume    = {66},
  number    = {2},
  pages     = {177 -- 184},
  year      = {2013},
}