@misc{indiciae948884cdbdaf,
  title = {Gravitons and loops.},
  author = {A Ashtekar and C Rovelli and L Smolin},
  year = {1991},
  doi = {10.1103/physrevd.44.1740},
  url = {https://pubmed.ncbi.nlm.nih.gov/10014054/},
  note = {Source identifier: 10014054}
}