@article{MZ_1962__78_170030,
     author = {Svetozar Kurepa},
     title = {On n-th {Roots} of {Normal} {Operators.}},
     journal = {Mathematische Zeitschrift},
     pages = {285--292},
     publisher = {mathdoc},
     volume = {78},
     year = {1962},
     zbl = {0103.08502},
     url = {http://geodesic.mathdoc.fr/item/MZ_1962__78_170030/}
}