@article{GeoPop:03,
  journal = {Tatra Mt. Math. Publ.},
  volume = {27},
  title = {Closure operators and concept equations in non-commutative fuzzy
           logic},
  year = {2003},
  fjournal = {Tatra Mountains Mathematical Publications},
  pages = {67--90},
  author = {Georgescu, George and Popescu, Andrei},
  note = {General algebra and ordered sets},
}