@misc{indiciae7992669a6193,
  title = {Addition Formulae for Spheroidal Functions.},
  author = {P M Morse},
  year = {1935},
  doi = {10.1073/pnas.21.1.56},
  url = {https://pubmed.ncbi.nlm.nih.gov/16577658/},
  note = {Source identifier: 16577658}
}