@misc{indiciaea76b16e114d5,
  title = {Levinson's theorem for Dirac particles with a long-range potential.},
  author = {ZQ Ma},
  year = {1985},
  doi = {10.1103/physrevd.32.2213},
  url = {https://pubmed.ncbi.nlm.nih.gov/9956397/},
  note = {Source identifier: 9956397}
}