1. Pseudo-Differential Operators: An Introduction;Friedrichs,1968
2. An algebra of pseudo-differential operators;Kohn;Comm. Pure Appl. Math.,1965
3. Pseudo-differential operators and the uniqueness of the Cauchy problem;Kumano-Co;Comm. Pure Appl. Math.,1969
4. Scattering theory for wave propagation problems of classical physics by the method of Lax and Phillips;LaVita,1971
5. Scattering Theory;Lax,1967