@article{CMUC_1993__34_3_a19,
     author = {Ugle\v{s}i\'c, N.},
     title = {An example in the theory of approximate systems},
     journal = {Commentationes Mathematicae Universitatis Carolinae},
     pages = {575--581},
     publisher = {mathdoc},
     volume = {34},
     number = {3},
     year = {1993},
     mrnumber = {1243089},
     zbl = {0785.54017},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/CMUC_1993__34_3_a19/}
}