@article{RO_1989__23_4_393_0,
     author = {Batbedat, Andr\'e},
     title = {Sur les orientations d'une ultram\'etrique ou d'une hi\'erarchie},
     journal = {RAIRO - Operations Research - Recherche Op\'erationnelle},
     pages = {393--403},
     publisher = {EDP-Sciences},
     volume = {23},
     number = {4},
     year = {1989},
     mrnumber = {1036702},
     zbl = {0681.62055},
     language = {fr},
     url = {http://www.numdam.org/item/RO_1989__23_4_393_0/}
}