@article{PIM_1977_N_S_21_35_a25,
     author = {Bojan Popovi\'c},
     title = {On {Definiteness} {Of} {Certain} {Matrix} {Functions} {Of} {A} {Matrix}},
     journal = {Publications de l'Institut Math\'ematique},
     pages = {165 },
     publisher = {mathdoc},
     volume = {_N_S_21},
     number = {35},
     year = {1977},
     url = {http://geodesic.mathdoc.fr/item/PIM_1977_N_S_21_35_a25/}
}