@misc{indiciae93ed9b5bb15d,
  title = {Zonal and tesseral harmonic coefficients for the geopotential function, from zero to 18th order},
  author = {Kirkpatrick, J. C.},
  year = {1976},
  url = {https://ntrs.nasa.gov/citations/19760020843},
  note = {Source identifier: 19760020843}
}