@article{PIM_1969_N_S_09_23_a11,
     author = {Bogoljub Stankovi\'c},
     title = {The {Existence} {And} {The} {Unicity} {Of} {Solution} {Of} {A} {System} {Of} {Operator} {Differential} {Equations}},
     journal = {Publications de l'Institut Math\'ematique},
     pages = {85 },
     year = {1969},
     volume = {_N_S_09},
     number = {23},
     url = {http://geodesic.mathdoc.fr/item/PIM_1969_N_S_09_23_a11/}
}