@misc{indiciae739cebdf6caa,
  title = {A Shifted Block Lanczos Algorithm 1: The Block Recurrence},
  author = {Grimes, Roger G. and Lewis, John G. and Simon, Horst D.},
  year = {1990},
  url = {https://ntrs.nasa.gov/citations/19970014139},
  note = {Source identifier: 19970014139}
}