@article{CC_2008_37_3_a2,
     author = {Duda, Zdzis{\l}aw},
     title = {On some nonconventional problem of a state filtration},
     journal = {Control and Cybernetics},
     pages = {531--547},
     publisher = {mathdoc},
     volume = {37},
     number = {3},
     year = {2008},
     zbl = {1177.93079},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/CC_2008_37_3_a2/}
}