In this paper, we derive eight basic identities of symmetry in three
variables related to generalized Bernoulli polynomials and generalized power
sums. All of these are new, since there have been results only about identities
of symmetry in two variables. The derivations of identities are based on the
$p$-adic integral expression of the generating function for the generalized
Bernoulli polynomials and the quotient of $p$-adic integrals that can be
expressed as the exponential generating function for the generalized power
sums.