@article{AUPO_1986__25_1_a3,
     author = {Stan\v{e}k, Svatoslav},
     title = {A phase of the differential equation $y'=Q(t)y$ with a complex coefficient $Q$ of the real variable},
     journal = {Acta Universitatis Palackianae Olomucensis. Facultas Rerum Naturalium. Mathematica},
     pages = {57--75},
     publisher = {mathdoc},
     volume = {25},
     number = {1},
     year = {1986},
     mrnumber = {918369},
     zbl = {0645.34007},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/AUPO_1986__25_1_a3/}
}