@article{AUPO_1990_29_1_a9,
     author = {Vl\v{c}ek, Vladim{\'\i}r},
     title = {To existence of the periodic solution of a third-order nonlinear differential equation},
     journal = {Acta Universitatis Palackianae Olomucensis. Facultas Rerum Naturalium. Mathematica},
     pages = {123--163},
     year = {1990},
     volume = {29},
     number = {1},
     mrnumber = {1144836},
     zbl = {0754.34037},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/AUPO_1990_29_1_a9/}
}