%0 Journal Article
%A Ya. B. Zel'dovich
%T The number of quanta as an invariant of classical electromagnetic field
%J Doklady Akademii Nauk
%D 1965
%P 1359-1360
%V 163
%N 6
%I mathdoc
%U http://geodesic.mathdoc.fr/item/DAN_1965_163_6_a16/
%G ru
%F DAN_1965_163_6_a16