@misc{indiciaef26bfdb627f7,
  title = {Recent developments in perturbation theory},
  author = {Brown, W. B. and Epstein, S. T. and Hirschfelder, J. O.},
  year = {1964},
  url = {https://ntrs.nasa.gov/citations/19650016348},
  note = {Source identifier: 19650016348}
}