@Article{GabrielsNavara:MathSlov12,
  IS = { zkontrolovano 30 Dec 2012 },
  UPDATE  = { 2012-12-27 },
  author =     {Gabri{\"e}ls, Jeannine J.~M. and Navara, Mirko },
  title =      {Associativity of operations on orthomodular lattices},
  journal =    {Mathematica Slovaca},
  publisher =  {Slovak Academy of Sciences},
  address =    {Bratislava, Slovakia},
  issn =       {0139-9918},
  authorship = {50-50},
  project =    {MSM 6840770038},
  year       = {2012},
month       = { July },
  pages      = {1069-1078},
  volume     = {62},
  number     = {6},
  annote =     {It is known that orthomodular lattices admit 96 binary
    operations, out of which 16 are commutative. We clarify which of
    them are associative.},
  keywords =   {orthomodular lattice, free lattice, ideal, congruence,
    commutator, associativity, commutativity, focusing,
    Foulis--Holland theorem, implication, equivalence, variety},
  psurl       = {[PDF] },
}