References
- Gelfand , I. M. and Shilov , G. E. 1964 . Generalized Functions , New York : Academic Press, Inc. .
- Hurwitz , A. and Courant , R. 1964. . Theory of Functions , Springer-Verlag .
- Halmos , P. R. 1957 . Introduction to Hilbert Space , New York : Chelsea Pub. Comp. .