TY  - RPRT
TI  - INTEGRATION OVER HILBERT SPACE AND OUTER EXTENSIONS.
AU  - K O Friedrichs
AU  - H N Shapiro
PY  - 1957
DO  - 10.1073/pnas.43.4.336
UR  - https://pubmed.ncbi.nlm.nih.gov/16578474/
ID  - 16578474
ER  -