%0 Journal Article %A Kiguradze, Ivan T. %A Rachůnková, Irena %T On a certain nonlinear problem for two-dimensional differential systems %J Archivum mathematicum %D 1980 %P 15-37 %V 16 %N 1 %I mathdoc %U http://geodesic.mathdoc.fr/item/ARM_1980__16_1_a2/ %G en %F ARM_1980__16_1_a2