@misc{1160476,
  author = {Frank Heinrich},
  title = {The network security center:},
  year = {1978},
  month = {1978-01-01 05:01:00},
  publisher = {, National Institute of Standards and Technology, Gaithersburg, MD},
  doi = {https://doi.org/10.6028/NBS.SP.500-21v2},
  language = {en},
}