TY  - JOUR
AU  - Andres, Ján
AU  - Vlček, Vladimír
TI  - Note to the existence of periodic solutions for higher-order differential equations with nonlinear restoring term and time-variable coefficients
JO  - Acta Universitatis Palackianae Olomucensis. Facultas Rerum Naturalium. Mathematica
PY  - 1991
SP  - 149
EP  - 157
VL  - 30
IS  - 1
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/AUPO_1991__30_1_a13/
LA  - en
ID  - AUPO_1991__30_1_a13
ER  -