Vv. Nesterenko et Ig. Pirozhenko, Direct mode summation for the Casimir energy of a spherical shell and a compact ball, PHYS ATOM N, 63(4), 2000, pp. 668-671
A simple method for calculating the Casimir energy for a sphere and a compa
ct ball is developed on the basis of a direct mode summation by means of co
ntour integration in a complex plane of eigenfrequencies. (C) 2000 MAIK "Na
uka/Interperiodica".