@misc{indiciae0af3d214d21a,
  title = {EIGENFUNCTION EXPANSIONS FOR FORMALLY SELF-ADJOINT PARTIAL DIFFERENTIAL OPERATORS. II.},
  author = {F E Browder},
  year = {1956},
  doi = {10.1073/pnas.42.11.870},
  url = {https://pubmed.ncbi.nlm.nih.gov/16589961/},
  note = {Source identifier: 16589961}
}