@misc{indiciaeb5c9e47fd802,
  title = {Hexagonal multiple phase-and-amplitude-shift-keyed signal sets},
  author = {Simon, M. K. and Smith, J. G.},
  year = {1973},
  url = {https://ntrs.nasa.gov/citations/19740027790},
  note = {Source identifier: 19740027790}
}