@article{GeoPop:04a,
  journal = {Fuzzy Sets and Systems},
  volume = {143},
  title = {Non-commutative fuzzy structures and pairs of weak negations},
  year = {2004},
  fjournal = {Fuzzy Sets and Systems. An International Journal in Information
              Science and Engineering},
  pages = {129--155},
  number = {1},
  author = {Georgescu, George and Popescu, Andrei},
  note = {Advances in fuzzy logic},
}