@misc{indiciaec1a8fa22ada4,
  title = {Mass in Curved Space-Time.},
  author = {G Y Rainich},
  year = {1926},
  doi = {10.1073/pnas.12.2.110},
  url = {https://pubmed.ncbi.nlm.nih.gov/16587064/},
  note = {Source identifier: 16587064}
}