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@article{ARM_1970__6_1_a3, author = {Vosmansk\'y, Jarom{\'\i}r}, title = {Monotonic properties of zeros and extremants of the differential equation $y''+q(t)y=0$}, journal = {Archivum mathematicum}, pages = {37--74}, publisher = {mathdoc}, volume = {06}, number = {1}, year = {1970}, mrnumber = {0296420}, zbl = {0239.34014}, language = {en}, url = {http://geodesic.mathdoc.fr/item/ARM_1970__6_1_a3/} }
Vosmanský, Jaromír. Monotonic properties of zeros and extremants of the differential equation $y''+q(t)y=0$. Archivum mathematicum, Tome 06 (1970) no. 1, pp. 37-74. http://geodesic.mathdoc.fr/item/ARM_1970__6_1_a3/