@article{ARM_1980__16_1_a2,
     author = {Kiguradze, Ivan T. and Rach\r{u}nkov\'a, Irena},
     title = {On a certain nonlinear problem for two-dimensional differential systems},
     journal = {Archivum mathematicum},
     pages = {15--37},
     publisher = {mathdoc},
     volume = {16},
     number = {1},
     year = {1980},
     mrnumber = {594664},
     zbl = {0465.34004},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/ARM_1980__16_1_a2/}
}