1. Difference equations and functional equations in transmission line theory;Redheffer,1961
2. Functional equations, wave propagation and invariant imbedding;Bellman;J. Math. Mech.,1959
3. Inequalities for a Matrix Riccati equation;Redheffer;J. Math. Mech.,1959
4. Solutions of a Riccati matrix differential equation as functions of initial values;Reid;J. Math. Mech.,1959
5. A study of wave propagation through a plasma using coupled mode technique;Letton,1966