@misc{1153121,
  author = {Richard H Johns},
  title = {Reference materials for collaborative tests of air quality methods:},
  year = {1974},
  month = {1974-01-01 05:01:00},
  publisher = {, National Institute of Standards and Technology, Gaithersburg, MD},
  doi = {https://doi.org/10.6028/NBS.TN.840},
  language = {en},
}