1. J. L. Lions, Optimal Control of Systems Governed by Partial Differential Equations (Springer-Verlag, N.Y., 1971).
2. N. U. Ahmed and K. L. Teo, Optimal Control of Distributed Parameter Systems (North Holland, N.Y., 1981).
3. A. G. Butkovsky, Optimal Control of Distributed Parameter Systems (Elsevier, N.Y., 1969).
4. W. Krabs, Optimal Control of Undamped Linear Vibrations (Heldermann, Lemgo, 1995).
5. J. E. Lagnese, G. Leugering, and E. J. P. G. Schmidt, Modeling, Analysis and Control of Dynamic Elastic Multi-Link Structures (Birkhäuser, Boston, 1984).