%0 Journal Article %A A. Kh. Stash %T Properties of Sergeev oscilation characteristics of periodic second-order equation %J Vladikavkazskij matematičeskij žurnal %D 2021 %P 78-86 %V 23 %N 2 %I mathdoc %U http://geodesic.mathdoc.fr/item/VMJ_2021_23_2_a6/ %G ru %F VMJ_2021_23_2_a6