“…The exact boundary controllability and stabilization of Maxwell's equations have been studied by many authors [4,6,7,8,10,13,15,17,18,19,21] and are usually based on an observability estimate obtained by different methods like the multiplier method, microlocal analysis, the frequency domain method. A similar strategy leads to the internal controllability of Maxwell's equations, see for instance [17,18,22,23].…”