@misc{indiciae82be9b2ff40d,
  title = {Combining quantum and classical perturbation theories.},
  author = {JH Jensen},
  year = {1992},
  doi = {10.1103/physreva.45.2686},
  url = {https://pubmed.ncbi.nlm.nih.gov/9907295/},
  note = {Source identifier: 9907295}
}