@misc{indiciaed067a6a677aa,
  title = {What does operator do in complex systems.},
  author = {J M Christensen and R G Mills},
  year = {1967},
  doi = {10.1177/001872086700900406},
  url = {https://pubmed.ncbi.nlm.nih.gov/5584848/},
  note = {Source identifier: 5584848}
}