@misc{indiciae5b602f9640aa,
  title = {An inexpensive level detector.},
  author = {M E Swinnen},
  year = {1967},
  doi = {10.1111/j.1469-8986.1967.tb02713.x},
  url = {https://pubmed.ncbi.nlm.nih.gov/6038678/},
  note = {Source identifier: 6038678}
}