@misc{indiciae6cbd8293146d,
  title = {Preliminary report on the operations of the coal-testing plant of the United States Geological Survey at the Louisiana Purchase Exposition, St. Louis, Missouri, 1904},
  author = {Edward Wheeler Parker and Joseph A. Holmes and Marius R. Campbell},
  year = {1905},
  doi = {10.3133/b261},
  url = {https://pubs.usgs.gov/publication/b261},
  note = {Source identifier: b261}
}