@article{NUMA_1966__9_131741,
     author = {B. PENKOV and BL. SENDOV},
     title = {Hausdorffsche {Metrik} und {Approximationen.}},
     journal = {Numerische Mathematik},
     pages = {214--226},
     publisher = {mathdoc},
     volume = {9},
     year = {1966},
     url = {http://geodesic.mathdoc.fr/item/NUMA_1966__9_131741/}
}