@misc{indiciae3c23f87079ab,
  title = {Variational procedure for time-dependent processes.},
  author = {R Englman and A Yahalom},
  year = {2004},
  doi = {10.1103/physreve.69.026120},
  url = {https://pubmed.ncbi.nlm.nih.gov/14995533/},
  note = {Source identifier: 14995533}
}