@misc{indiciaea1370bd92d3c,
  title = {INTEGRATION OVER HILBERT SPACE AND OUTER EXTENSIONS.},
  author = {K O Friedrichs and H N Shapiro},
  year = {1957},
  doi = {10.1073/pnas.43.4.336},
  url = {https://pubmed.ncbi.nlm.nih.gov/16578474/},
  note = {Source identifier: 16578474}
}