@article{AUPO_1972__12_1_a2,
     author = {Krbi\v{l}a, Jaroslav},
     title = {A note on the definiteness of the differential equations $y'' = q(t)y$},
     journal = {Acta Universitatis Palackianae Olomucensis. Facultas Rerum Naturalium. Mathematica},
     pages = {19--22},
     publisher = {mathdoc},
     volume = {12},
     number = {1},
     year = {1972},
     mrnumber = {0379949},
     zbl = {0412.34019},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/AUPO_1972__12_1_a2/}
}