@misc{W2007995029,
  author = {G. N. Lance and W. T. Williams},
  title = {A General Theory of Classificatory Sorting Strategies: 1. Hierarchical Systems},
  year = {1967},
  howpublished = {The Computer Journal},
  doi = {https://doi.org/10.1093/comjnl/9.4.373}
}