@misc{indiciae21f9a7645df9,
  title = {Variational calculations and Bogolubov transformations.},
  author = {J Wudka},
  year = {1989},
  doi = {10.1103/physrevd.39.3000},
  url = {https://pubmed.ncbi.nlm.nih.gov/9959530/},
  note = {Source identifier: 9959530}
}