@article {GreifVarah1998,
    AUTHOR = {Greif, Chen and Varah, James},
     TITLE = {Iterative solution of cyclically reduced systems arising from
              discretization of the three-dimensional convection-diffusion
              equation},
   JOURNAL = {SIAM J. Sci. Comput.},
    VOLUME = {19},
      YEAR = {1998},
    NUMBER = {6},
     PAGES = {1918--1940}
}