@article{JCA_1998_5_1_a6,
     author = {M. Niezgoda},
     title = {On {Schur-Ostrowski} {Type} {Theorems} for {Group} {Majorizations}},
     journal = {Journal of convex analysis},
     pages = {081--106},
     year = {1998},
     volume = {5},
     number = {1},
     url = {http://geodesic.mathdoc.fr/item/JCA_1998_5_1_a6/}
}