@misc{210141,
  author = {Frank Heinrich},
  title = {The Network Security Center: a System Level Approach to Computer Network Security},
  year = {1978},
  month = {1978-01-01},
  publisher = {Special Publication (NIST SP), National Institute of Standards and Technology, Gaithersburg, MD},
  doi = {https://doi.org/10.6028/NBS.SP.500-21v2},
  language = {en},
}