@article{ELMA_1979__34_141228,
     author = {M.S. Klamkin},
     title = {Triangle inequalities from the triangle inequality.},
     journal = {Elemente der Mathematik},
     pages = {49--55},
     publisher = {mathdoc},
     volume = {34},
     year = {1979},
     zbl = {0399.51012},
     url = {http://geodesic.mathdoc.fr/item/ELMA_1979__34_141228/}
}