K 60.narozeninám prof. RNDr. Ladislava Sedláčka, CSc. (Czech) [Professor Ladislav Sedláček (on the occasion of his sixtieth birthday)]. Acta Universitatis Palackianae Olomucensis. Facultas Rerum Naturalium. Mathematica, vol. 22 (1983), issue 1, pp. 5-7