%0 Journal Article
%A Celso Martínez
%A Miguel Sanz
%T N-th roots of a non-negative operator: conditions for uniqueness.
%J Manuscripta mathematica
%D 1989
%P 403-418
%V 64
%N 2
%I mathdoc
%U http://geodesic.mathdoc.fr/item/MM2_1989__64_2_155415/
%F MM2_1989__64_2_155415