1. Optimal Control of Differential and Functional Equations;Warga,1972
2. Strongly and weakly relaxed controls for time delay systems;Rosenblueth;SIAM Journal on Control and Optimization,1992
3. Approximation of strongly relaxed minimizers with ordinary delayed controls;Rosenblueth;Applied Mathematics and Optimization,1995
4. Relaxation of delayed controls: A review;Rosenblueth;IMA Journal of Mathematical Control and Information,1995
5. Relaxation procedures for time delay systems;Rosenblueth;Journal of Mathematical Analysis and Applications,1991