@misc{indiciae02ebe2decead,
  title = {Integrated and integral Hellmann-Feynman formulas.},
  author = {Epstein, S. T. and Hurley, A. C. and Parr, R. G. and Wyatt, R. E.},
  year = {1967},
  url = {https://ntrs.nasa.gov/citations/19670060908},
  note = {Source identifier: 19670060908}
}