@misc{indiciae4c7decb6a665,
  title = {Controllability of nearly nonnegative linear systems using positive controls},
  author = {Perry, T. S. and Gunderson, R. W.},
  year = {1977},
  url = {https://ntrs.nasa.gov/citations/19770055136},
  note = {Source identifier: 19770055136}
}