@article{PIM_1963_N_S_03_17_a16,
     author = {Dragomir \v{Z}. {\DJ}okovi\'c},
     title = {A {Theorem} {On} {Semigroups} {Of} {Linear} {Operators}},
     journal = {Publications de l'Institut Math\'ematique},
     pages = {129 },
     publisher = {mathdoc},
     volume = {_N_S_03},
     number = {17},
     year = {1963},
     url = {http://geodesic.mathdoc.fr/item/PIM_1963_N_S_03_17_a16/}
}