1. Boas, R. P. 1954. “Entire functions”. New York: Academic Press Inc.
2. Dautray, R. and Lions, J. L., eds. 1984. Analyse mathématiques et calcul numérique, Mas-son.
3. Titchmarsh, E. C. 1948. “Introduction to the theory of Fourier integrals”. Oxford University Press. second edition
4. Yosida, K. 1980. “Functional analysis”. Springer-Verlag. sixth edition