1. Perturbation Methods in Applied Mathematics;Cole;Blaisdell Publ. Comp.,1968
2. Dyke, M.V. (1964). Perturbation Methods in Fluid Mechanics. Academic Press, New York, London.
3. Study of phase self-tuning with high order filters by asymptotic methods;Evtyanov;Radiotekhnika,1968
4. Asymptotic phenomena in mathematical physics;Fridrichs;Bull. Amer. Math. Soc.,1955
5. An algorithm for approximate solutions to weakly filtered synchronous control systems and nonlinear renewal processes;Hoppensteadt;SIAM J. Appl. Math.,1983