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@article{ARM_1976__12_4_a0, author = {Bartu\v{s}ek, Miroslav}, title = {Monotonicity theorems concerning differential equations $y''+f(t,y,y')=0$}, journal = {Archivum mathematicum}, pages = {169--178}, publisher = {mathdoc}, volume = {12}, number = {4}, year = {1976}, mrnumber = {0430410}, zbl = {0354.34031}, language = {en}, url = {http://geodesic.mathdoc.fr/item/ARM_1976__12_4_a0/} }
Bartušek, Miroslav. Monotonicity theorems concerning differential equations $y''+f(t,y,y')=0$. Archivum mathematicum, Tome 12 (1976) no. 4, pp. 169-178. http://geodesic.mathdoc.fr/item/ARM_1976__12_4_a0/