@misc{indiciae1558377e1cd8,
  title = {Nondegenerate real-valued differentiable functions.},
  author = {M Morse},
  year = {1967},
  doi = {10.1073/pnas.57.1.32},
  url = {https://pubmed.ncbi.nlm.nih.gov/16591448/},
  note = {Source identifier: 16591448}
}