@misc{indiciae77e087fd26a3,
  title = {Methods for collecting algal samples as part of the National Water-Quality Assessment Program},
  author = {Stephen D. Porter and Thomas F. Cuffney and Martin E. Gurtz and Michael R. Meador},
  year = {1993},
  doi = {10.3133/ofr93409},
  url = {https://pubs.usgs.gov/publication/ofr93409},
  note = {Source identifier: ofr93409}
}