@misc{indiciae68fcdefbe1da,
  title = {Modifications of two palynological processing techniques; ultrasonic processing and early-stage sieving},
  author = {T.P. Sheehan},
  year = {1992},
  doi = {10.3133/ofr92564},
  url = {https://pubs.usgs.gov/publication/ofr92564},
  note = {Source identifier: ofr92564}
}