@article{10_21136_MB_1995_126223,
     author = {Zyskowska, Krystyna},
     title = {On an extremal problem},
     journal = {Mathematica Bohemica},
     pages = {113--124},
     publisher = {mathdoc},
     volume = {120},
     number = {2},
     year = {1995},
     doi = {10.21136/MB.1995.126223},
     mrnumber = {1357596},
     zbl = {0857.30016},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.21136/MB.1995.126223/}
}