@misc{indiciae7350e49f1846,
  title = {Upper and lower covariance bounds for perturbed linear systems},
  author = {Xu, J.-H. and Skelton, R. E. and Zhu, G.},
  year = {1990},
  url = {https://ntrs.nasa.gov/citations/19900064037},
  note = {Source identifier: 19900064037}
}