@misc{1170326,
  author = {W A Horn},
  title = {Some recent theoretical work on accessibility in transportation systems:},
  year = {1971},
  month = {1971-01-01 05:01:00},
  publisher = {, National Institute of Standards and Technology, Gaithersburg, MD},
  doi = {https://doi.org/10.6028/NBS.RPT.10500},
  language = {en},
}