@article{AUPO_1977__16_1_a7,
     author = {Vl\v{c}ek, Vladim{\'\i}r},
     title = {Conjugate points of solutions of a fourth-order iterated linear differential equation},
     journal = {Acta Universitatis Palackianae Olomucensis. Facultas Rerum Naturalium. Mathematica},
     pages = {95--122},
     publisher = {mathdoc},
     volume = {16},
     number = {1},
     year = {1977},
     mrnumber = {0594951},
     zbl = {0392.34004},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/AUPO_1977__16_1_a7/}
}