%0 Journal Article
%A V. V. Val'kov
%T Unitary transformations of the group~$U(N)$ and diagonalization of multilevel Hamiltonians
%J Teoretičeskaâ i matematičeskaâ fizika
%D 1988
%P 143-152
%V 76
%N 1
%I mathdoc
%U http://geodesic.mathdoc.fr/item/TMF_1988_76_1_a11/
%G ru
%F TMF_1988_76_1_a11