@misc{indiciae2bb9f7718743,
  title = {Contraction groups and equivalent norms},
  author = {Buis, G. R. and Eisen, M. M. and Vogt, W. G.},
  year = {1968},
  url = {https://ntrs.nasa.gov/citations/19680017987},
  note = {Source identifier: 19680017987}
}