@article{PMFA_1957__2_2_a0,
     author = {H\'ajek, Otomar},
     title = {Singularity diferenci\'aln{\'\i} rovnice. {II}},
     journal = {Pokroky matematiky, fyziky a astronomie},
     pages = {137--143},
     publisher = {mathdoc},
     volume = {02},
     number = {2},
     year = {1957},
     language = {cz},
     url = {http://geodesic.mathdoc.fr/item/PMFA_1957__2_2_a0/}
}