1. J. L. Lions, Optimal Control of Systems Governed by Partial Differential Equations (Springer, New York, 1971).
2. N. U. Ahmed and K. L. Teo, Optimal Control of Distributed Parameter Systems (North-Holland, New York, 1981).
3. A. G. Butkovsky, Distributed Control Systems (Elsevier, New York, 1969).
4. W. Krabs, Optimal Control of Undamped Linear Vibrations (Heldermann, Lemgo, 1995).
5. M. Gugat, “Optimal control of networked hyperbolic systems: evaluation of derivatives,” Adv. Modell. Optimiz. 7, 9–37 (2005).