@misc{indiciae2a6dfa2ade90,
  title = {Effective density matrix for free-electron-laser radiation.},
  author = {I Gjaja and A Bhattacharjee},
  year = {1991},
  doi = {10.1103/physreva.43.3206},
  url = {https://pubmed.ncbi.nlm.nih.gov/9905401/},
  note = {Source identifier: 9905401}
}