@misc{1191956,
  author = {Ralph Edgar Gould},
  title = {Circular of the Bureau of Standards no. 402::sundials},
  year = {1933},
  month = {1933-01-01 05:01:00},
  publisher = {, National Institute of Standards and Technology, Gaithersburg, MD},
  doi = {https://doi.org/10.6028/NBS.CIRC.402},
  language = {en},
}