@misc{indiciae877e11579d3c,
  title = {Implications of the activity factor.},
  author = {M E Hoppa and G D Roberts},
  year = {1974},
  doi = {10.1093/geront/14.4.331},
  url = {https://pubmed.ncbi.nlm.nih.gov/4470515/},
  note = {Source identifier: 4470515}
}