%0 Journal Article
%A E. V. Derunova
%A Yu. I. Sapronov
%T Application of normalized key functions in a~problem of branching of periodic extremals
%J Izvestiâ vysših učebnyh zavedenij. Matematika
%D 2015
%P 14-24
%N 8
%I mathdoc
%U http://geodesic.mathdoc.fr/item/IVM_2015_8_a1/
%G ru
%F IVM_2015_8_a1