@misc{indiciae02c400ff9db2,
  title = {Libration in the earth's rotation},
  author = {Chao, B. F. and Liu, H. S. and Dong, D. N. and Herring, T. A.},
  year = {1991},
  url = {https://ntrs.nasa.gov/citations/19920030320},
  note = {Source identifier: 19920030320}
}