@article{10_14708_cm_v13i2_5676,
     author = {Z. Polniakowski},
     title = {On the differential equation \(y''-a(x)y =0\)},
     journal = {Commentationes Mathematicae},
     pages = { 241--248},
     publisher = {mathdoc},
     volume = {13},
     number = {2},
     year = {1970},
     doi = {10.14708/cm.v13i2.5676},
     language = {pl},
     url = {http://geodesic.mathdoc.fr/articles/10.14708/cm.v13i2.5676/}
}