@misc{indiciaee176b08dbae6,
  title = {NON-OBSTRUCTING SETS AND RELATED MAPPINGS.},
  author = {G T Whyburn},
  year = {1960},
  doi = {10.1073/pnas.46.9.1244},
  url = {https://pubmed.ncbi.nlm.nih.gov/16590742/},
  note = {Source identifier: 16590742}
}