S. Leseduarte et A. Romeo, ZETA-FUNCTION OF THE BESSEL OPERATOR ON THE NEGATIVE REAL AXIS, Journal of physics. A, mathematical and general, 27(7), 1994, pp. 2483-2495
We investigate the pole structure of the zeta function zetaA(nu) (s) =
SIGMA(k) lambda(k)-s built out of the eigenvalues lambda(k) of a Bess
el operator A(nu) subject to Dirichlet boundary conditions at one end
of the domain. This leads us to the study of zetaA(nu) on the negative
real axis, where most of the singularities occur.