@INPROCEEDINGS{NavaraGrado97,
  MYNOTE =   { S1997, A1997, P1997 },
  AUTHOR =   {Navara, Mirko},
  EDITOR =   {A.~Vol{\v c}i{\v c}},
  TITLE =   {Characterization of state spaces of orthomodular
                  structures},
  BOOKTITLE =   {Proc. Summer School on Measure Theory and Real
                  Analysis},
  PUBLISHER =   {Universit\`a Trieste},
  ADDRESS =   {Trieste, Italy},
  YEAR =   {1997},
  MONTH =   {September},
  PAGES =   {97--123},
}