@misc{indiciaef2141abdc03a,
  title = {Factorizations of two vector operators for the Coulomb problem.},
  author = {de Lange OL and RE Raab},
  year = {1987},
  doi = {10.1103/physreva.35.951},
  url = {https://pubmed.ncbi.nlm.nih.gov/9898232/},
  note = {Source identifier: 9898232}
}