@misc{indiciae9d8b3aa8e23c,
  title = {Optimal models for social change.},
  author = {G Houghton},
  year = {1967},
  doi = {10.1007/bf02476932},
  url = {https://pubmed.ncbi.nlm.nih.gov/5582158/},
  note = {Source identifier: 5582158}
}