1. Russak, I. B.,On Problems with Bounded State Variables, Journal of Optimization Theory and Applications, Vol. 5, No. 2, 1970.
2. Russak, I. B.,On Problems with Bounded State Variables, University of California at Los Angeles, Ph.D. Thesis, 1967.
3. Hestenes, M. R.,Calculus of Variations and Optimal Control Theory, John Wiley and Sons, New York, 1966.