@misc{indiciae01439140d25c,
  title = {Hercules X-1 = HZ Herculis - A multiperiod variable},
  author = {Wolff, C. L. and Kondo, Y.},
  year = {1978},
  url = {https://ntrs.nasa.gov/citations/19780038404},
  note = {Source identifier: 19780038404}
}