“…However, in this way the convergence of the resulting closed loop state is not better than z(t) = O( 1 √ t ). The problem of exponential stabilization of the system (1) has been considered in [11,34,36] with the following bounded feedback v(t) = −ρ z(t), Bz(t) z(t) 2 1 {t≥0; z(t) =0} , (5) where ρ > 0 is the gain control. Moreover, under the assumption (4), the exponential stabilization of (1) has been studied in [37] using the switching control w(t) = −ρ sign( z(t), Bz(t) ), ρ > 0.…”