Voir la notice de l'article provenant de la source eLibrary of Mathematical Institute of the Serbian Academy of Sciences and Arts
@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/} }
Bojan Popović. On Definiteness Of Certain Matrix Functions Of A Matrix. Publications de l'Institut Mathématique, _N_S_21 (1977) no. 35, p. 165 . http://geodesic.mathdoc.fr/item/PIM_1977_N_S_21_35_a25/