@article{ELMA_1989__44_3_141449,
     author = {W. Gmeiner},
     title = {A pair of general triangle inequalities.},
     journal = {Elemente der Mathematik},
     pages = {41--47},
     publisher = {mathdoc},
     volume = {44},
     number = {3},
     year = {1989},
     zbl = {0714.51012},
     url = {http://geodesic.mathdoc.fr/item/ELMA_1989__44_3_141449/}
}