%0 Journal Article %A Ł. Stettner %T Invariant measures of the pair: state, approximate filtering process %J Colloquium Mathematicum %D 1991 %P 347-351 %V 62 %N 2 %I mathdoc %U http://geodesic.mathdoc.fr/articles/10.4064/cm-62-2-347-351/ %R 10.4064/cm-62-2-347-351 %G en %F 10_4064_cm_62_2_347_351