@article{PIM_1971_N_S_11_25_a16,
     author = {M. Budim\v{c}evi\'c and B. Stankovi\'c},
     title = {The {Closure} {In} {The} {Space} {Of} {Mikusinski's} {Operators}},
     journal = {Publications de l'Institut Math\'ematique},
     pages = {115 },
     publisher = {mathdoc},
     volume = {_N_S_11},
     number = {25},
     year = {1971},
     url = {http://geodesic.mathdoc.fr/item/PIM_1971_N_S_11_25_a16/}
}