@misc{indiciae9dc51e136c32,
  title = {A seismic electronic system with automatic calibration and crystal reference},
  author = {John A. Rogers and Sam Maslak and John C. Lahr},
  year = {1980},
  doi = {10.3133/ofr80324},
  url = {https://pubs.usgs.gov/publication/ofr80324},
  note = {Source identifier: ofr80324}
}