@misc{1174371,
  author = {Thomas R Lettieri and Gary G Hembree},
  title = {Certification of NBS SRM 1691: 0.3�m-diameter polystyrene spheres:},
  year = {1988},
  month = {1988-01-01 05:01:00},
  publisher = {, National Institute of Standards and Technology, Gaithersburg, MD},
  doi = {https://doi.org/10.6028/NBS.IR.87-3730},
  language = {en},
}