%0 Journal Article
%A H. Lonka
%A O. Tammi
%T On the use of step-functions in extremum problems of the class with bounded boundary rotation
%J Annales Fennici Mathematici
%D 1968
%V 411-420
%I mathdoc
%U http://geodesic.mathdoc.fr/articles/10.5186/aasfm.1968.418/
%R 10.5186/aasfm.1968.418
%G en
%F AFM_1968_411-420_a2