@article{10_4064_cm_4_1_1_10,
     author = {J. Perkal},
     title = {Sur les ensembles \ensuremath{\varepsilon}-convexes},
     journal = {Colloquium Mathematicum},
     pages = {1--10},
     publisher = {mathdoc},
     volume = {4},
     number = {1},
     year = {1956},
     doi = {10.4064/cm-4-1-1-10},
     language = {fr},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/cm-4-1-1-10/}
}