@misc{indiciae863829d8a10b,
  title = {WAVE BRANCHING PROCESSES AND INVARIANT IMBEDDING, I.},
  author = {R Bellman and R Kalaba},
  year = {1961},
  doi = {10.1073/pnas.47.9.1507},
  url = {https://pubmed.ncbi.nlm.nih.gov/16590885/},
  note = {Source identifier: 16590885}
}