“…In recent years, these last two notions of strong and especially of uniform input-to-state stability have been intensively studied. See, for instance, [2], [10], [11], [12], [14], [5], [6], [15], [9], [13], [20], [7], [8], [23], [24] and the references therein. Also, weak input-to-state stability can be established for a rather large class of semilinear systems (both in the case of inputs entering in the domain and in the case of inputs entering at the boundary of the domain on which the partial differential equation describing the system lives).…”