@misc{indiciaea013e2071178,
  title = {Preconditioners for the spectral multigrid method},
  author = {Phillips, T. N. and Hussaini, M. Y. and Zang, T. A.},
  year = {1986},
  url = {https://ntrs.nasa.gov/citations/19870023276},
  note = {Source identifier: 19870023276}
}