@misc{indiciaedd9147fce7ac,
  title = {Laboratory and field testing of commercial rotational seismometers},
  author = {R.L. Nigbor and J.R. Evans and C. R. Hutt},
  year = {2009},
  doi = {10.1785/0120080247},
  url = {https://pubs.usgs.gov/publication/70036564},
  note = {Source identifier: 70036564}
}