@article{AUPO_1991__30_1_a14,
     author = {Vl\v{c}ek, Vladim{\'\i}r},
     title = {Periodic solutions of a parametric nonlinear third-order differential equation},
     journal = {Acta Universitatis Palackianae Olomucensis. Facultas Rerum Naturalium. Mathematica},
     pages = {159--188},
     publisher = {mathdoc},
     volume = {30},
     number = {1},
     year = {1991},
     mrnumber = {1166435},
     zbl = {0777.34031},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/AUPO_1991__30_1_a14/}
}