@misc{1185936,
  author = {Doyle A Ellerbruch and Donald R Belsher},
  title = {FM-CW electromagnetic technique of measuring coal layer thickness:},
  year = {1976},
  month = {1976-01-01 05:01:00},
  publisher = {, National Institute of Standards and Technology, Gaithersburg, MD},
  doi = {https://doi.org/10.6028/NBS.IR.76-840},
  language = {en},
}