@misc{indiciaeec1356656865,
  title = {Spectral element multigrid. Part 2: Theoretical justification},
  author = {Maday, Yvon and Munoz, Rafael},
  year = {1988},
  url = {https://ntrs.nasa.gov/citations/19890006303},
  note = {Source identifier: 19890006303}
}