@misc{indiciae056e3a31de87,
  title = {Quadratic invariance in linear systems.},
  author = {Aggarwal, J. K. and Mcclamroch, N. H.},
  year = {1967},
  url = {https://ntrs.nasa.gov/citations/19680033687},
  note = {Source identifier: 19680033687}
}