@misc{indiciaef0e0aa6c54df,
  title = {Perturbation of eigenfunction expansions.},
  author = {S T Kuroda},
  year = {1967},
  doi = {10.1073/pnas.57.5.1213},
  url = {https://pubmed.ncbi.nlm.nih.gov/16591558/},
  note = {Source identifier: 16591558}
}