@misc{indiciaef7779023694b,
  title = {Concerning Kendall's tau, a nonparametric correlation coefficient.},
  author = {M S SCHAEFFER and E E LEVITT},
  year = {1956},
  doi = {10.1037/h0045013},
  url = {https://pubmed.ncbi.nlm.nih.gov/13336201/},
  note = {Source identifier: 13336201}
}