@article{120175, author = {Vladim\'\i r Vl\v cek}, title = {On the focal points of solutions of a certain fourth order differential equation}, journal = {Acta Universitatis Palackianae Olomucensis. Facultas Rerum Naturalium. Mathematica}, volume = {25}, year = {1986}, pages = {97-115}, zbl = {0643.34040}, mrnumber = {918371}, language = {en}, url = {http://dml.mathdoc.fr/item/120175} }
Vlček, Vladimír. On the focal points of solutions of a certain fourth order differential equation. Acta Universitatis Palackianae Olomucensis. Facultas Rerum Naturalium. Mathematica, Tome 25 (1986) pp. 97-115. http://gdmltest.u-ga.fr/item/120175/
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