%0 Journal Article
%A Cui, Yan
%A Laurent, Camille
%A Wang, Zhiqiang
%T On the observability inequality of coupled wave equations: the case without boundary
%J ESAIM: Control, Optimisation and Calculus of Variations
%D 2020
%V 26
%I EDP-Sciences
%U http://www.numdam.org/articles/10.1051/cocv/2020004/
%R 10.1051/cocv/2020004
%G en
%F COCV_2020__26_1_A14_0