author = {Hackbusch, Wolfgang},
title = {{A fast iterative method for solving Helmholtz's equation in a general region}},
booktitle = {Computers, fast elliptic solvers, and applications : proceedings of the GAMM-Workshop
on Fast Solution Methods for the Discretized Poisson Equation, Karlsruhe, 1977},
editor = {Schumann, Ulrich},
publisher = {Advance Publications},
address = {London},
year = {1978},
pages = {182--188},
institution = {{Max Planck Institute for Mathematics in the Sciences}},