1. An overview on the solutions of the algebraic matrix Riccati equation and related problems;Jamshidi;Large Scale Systems,1980
2. Riccati Differential Equations;Reid,1965
3. On the conjugate point condition for the control problem;Breakwell;Int. J. Eng. Sci.,1965
4. On the Jacobi conditions for control problems with input delay;Razzaghi,1975
5. Conjugate point conditions for linear quadratic control problems;Razzaghi;Aut. Contr. Theory and Appl.,1978