@INPROCEEDINGS{PtakGrado97,
  MYNOTE =   { S1997, A1997, P1997 },
  Html =   { PtakGrado97 },
  AUTHOR =   {Pt{\'a}k, P.},
  EDITOR =   {A.~Vol\v ci\v c},
  TITLE =   {Observables},
  BOOKTITLE =   {Proc. Summer School on Measure Theory and Real
                  Analysis},
  PUBLISHER =   {Universit{\`a} Trieste},
  ADDRESS =   {Trieste, Italy},
  YEAR =   {1997},
  MONTH =   {September},
  PAGES =   {124--136},
  WHO =     {Navara},
}