%0 Journal Article
%A Takeaki Yamazaki
%T On upper and lower bounds of the numerical radius
 and an equality condition
%J Studia Mathematica
%D 2007
%P 83-89
%V 178
%N 1
%I mathdoc
%U http://geodesic.mathdoc.fr/articles/10.4064/sm178-1-5/
%R 10.4064/sm178-1-5
%G en
%F 10_4064_sm178_1_5