@misc{indiciae79c03dfdec12,
  title = {Retracting multifunctions.},
  author = {G T Whyburn},
  year = {1968},
  doi = {10.1073/pnas.59.2.343},
  url = {https://pubmed.ncbi.nlm.nih.gov/16591603/},
  note = {Source identifier: 16591603}
}