1. A. H. Jaffey, Rev. Scient. Instrum.25, 349 (1954).
2. K. A. Petrzhak and M. A. Buck, Sov. Phys. JTP25, 636 (1955) (in Russian).
3. P. M. Morse and H. Feshbach,Methods of Theoretical Physics, Part II. McGraw-Hill Book Co., New York 1953.
4. I. S. Gradshteyn and I. M. Ryzhik,Table of Integrals, Series and Products (formulae 3.152.1, 3.157.2, 3.169.1,2). Academic Press, New York 1980.