  The derivation of a convergent series representation for the quantum
electrodynamic effective action obtained by two of us (S.R.V. and D.R.L.) in
[Can. J. Phys. vol. 71, p. 389 (1993)] is reexamined. We present more details
of our original derivation. Moreover, we discuss the relation of the
electric-magnetic duality to the integral representation for the effective
action, and we consider the application of nonlinear convergence acceleration
techniques which permit the efficient and reliable numerical evaluation of the
quantum correction to the Maxwell Lagrangian.
