%0 Journal Article %A Tatjana Petek %A Valery G. Romanovski %T Time-reversibility and ivariants of some $3$-dim systems %J Buletinul Academiei de Ştiinţe a Republicii Moldova. Matematica %D 2023 %P 16-28 %N 1 %I mathdoc %U http://geodesic.mathdoc.fr/item/BASM_2023_1_a2/ %G en %F BASM_2023_1_a2