@misc{indiciae2dba2547d57e,
  title = {Maximal functions: Spherical means.},
  author = {E M Stein},
  year = {1976},
  doi = {10.1073/pnas.73.7.2174},
  url = {https://pubmed.ncbi.nlm.nih.gov/16592329/},
  note = {Source identifier: 16592329}
}