@article{PSMIR_1992___1_185_0,
     author = {Pelgrin, Xavier},
     title = {Un probl\`eme \`a fronti\`ere libre},
     journal = {Publications de l'Institut de recherche math\'ematiques de Rennes},
     pages = {185--191},
     publisher = {D\'epartement de Math\'ematiques et Informatique, Universit\'e de Rennes},
     number = {1},
     year = {1992},
     language = {fr},
     url = {http://www.numdam.org/item/PSMIR_1992___1_185_0/}
}