Nonlinear differential equations and algebraic systems. Williams, Lloyd K. — 1978 International Journal of Mathematics and Mathematical Sciences
Riccati equations. Williams, Lloyd K. — 1987 International Journal of Mathematics and Mathematical Sciences
Functional differential equations - a reciprocity principle. Williams, Lloyd K. — 1986 International Journal of Mathematics and Mathematical Sciences
Linear and Riccati matrix equations. Williams, Lloyd K. — 1989 International Journal of Mathematics and Mathematical Sciences