@misc{indiciae70e0e977a84f,
  title = {THE EIGENFUNCTION EXPANSION THEOREM FOR THE GENERAL SELF-ADJOINT SINGULAR ELLIPTIC PARTIAL DIFFERENTIAL OPERATOR. I. THE ANALYTICAL FOUNDATION.},
  author = {F E Browder},
  year = {1954},
  doi = {10.1073/pnas.40.6.454},
  url = {https://pubmed.ncbi.nlm.nih.gov/16589505/},
  note = {Source identifier: 16589505}
}