%0 Journal Article
%A L. V. Detchenya
%A A. P. Sadovskii
%T Letter to the editors: ``Orbital normal forms of two-dimensional analytic systems with zero linear and nonzero quadratic parts'' [Differ. Uravn. \textbf{35} (1999), no. 1, 51--57, 141; MR1723202]
%J Differencialʹnye uravneniâ
%D 2000
%P 1580
%V 36
%N 11
%I mathdoc
%U http://geodesic.mathdoc.fr/item/DE_2000_36_11_a21/
%G ru
%F DE_2000_36_11_a21