O vlastnostech řešení diferenciální rovnice $y^{(4)} +p(x) y''+q(x) y = 0$.
(Czech) [On properties of solutions of the differential equation $y^{(4)} +p(x) y''+q(x) y = 0$].Časopis pro pěstování matematiky,
vol. 93
(1968),
issue 2,
pp. 201-216
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