@misc{indiciae85a3cc1051a8,
  title = {Characteristic classes and weyl tensor: applications to general relativity.},
  author = {A Avez},
  year = {1970},
  doi = {10.1073/pnas.66.2.265},
  url = {https://pubmed.ncbi.nlm.nih.gov/16591838/},
  note = {Source identifier: 16591838}
}