1. The calculus of variations and functional analysis with optimal control and applications in mechanics, L. P. Lebedev and M. J. Cloud, WorldScientific, Singapore, 2003, xiii+420pp., Price $94.00, ISBN: 981-238-581-9 2. An introduction to modern variational techniques in mechanics and engineering, B. Z. Vujanovic and T. M. Atanackovic, Birkhäuser, Boston, MA, 2004, x+346pp., Price $74.95, ISBN: 0-8176-3399-5 - Subbaram Naidu, D. (International journal of robust and nonlinear control, 2006)