@article{GDZPPN002079917, title = {Triangle inequalities from the triangle inequality.}, journal = {Elemente der Mathematik}, volume = {34}, year = {1979}, pages = {49-55}, zbl = {0399.51012}, url = {http://dml.mathdoc.fr/item/GDZPPN002079917} }
Klamkin, M.S. Triangle inequalities from the triangle inequality.. Elemente der Mathematik, Tome 34 (1979) pp. 49-55. http://gdmltest.u-ga.fr/item/GDZPPN002079917/