%0 Journal Article
%A V. K. Romanko
%T Systems with first order derivative in the ``time''
%J Differencialʹnye uravneniâ
%D 1969
%P 174-185
%V 5
%N 1
%I mathdoc
%U http://geodesic.mathdoc.fr/item/DE_1969_5_1_a13/
%G ru
%F DE_1969_5_1_a13