@article{CMJ_2009__59_1_a13,
     author = {Zhang, Xiao-Dong and Ding, Chang-Xing},
     title = {The equality cases for the inequalities of {Oppenheim} and {Schur} for positive semi-definite matrices},
     journal = {Czechoslovak Mathematical Journal},
     pages = {197--206},
     publisher = {mathdoc},
     volume = {59},
     number = {1},
     year = {2009},
     mrnumber = {2486625},
     zbl = {1224.15042},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/CMJ_2009__59_1_a13/}
}