@misc{indiciae33f8baf7576b,
  title = {HANDTC, a Fortran program to calculate innerzone terrain corrections},
  author = {J.B. Spielman and David A. Ponce},
  year = {1984},
  doi = {10.3133/ofr84777},
  url = {https://pubs.usgs.gov/publication/ofr84777},
  note = {Source identifier: ofr84777}
}