@misc{indiciaec9a7e82444de,
  title = {Equations for the correlation functions using a generalized Keldysh technique.},
  author = {SM Kogan},
  year = {1991},
  doi = {10.1103/physreva.44.8072},
  url = {https://pubmed.ncbi.nlm.nih.gov/9905960/},
  note = {Source identifier: 9905960}
}