@article {GreifVarah1999, AUTHOR = {Greif, Chen and Varah, James}, TITLE = {Block stationary methods for nonsymmetric cyclically reduced systems arising from three-dimensional elliptic equations}, JOURNAL = {SIAM J. Matrix Anal. Appl.}, VOLUME = {20}, YEAR = {1999}, NUMBER = {4}, PAGES = {1038--1059} }