@misc{indiciae9b2233de05c8,
  title = {QCD sum rules and neutron-proton mass difference.},
  author = {KC Yang and WY Hwang and EM Henley and LS Kisslinger},
  year = {1993},
  doi = {10.1103/physrevd.47.3001},
  url = {https://pubmed.ncbi.nlm.nih.gov/10015904/},
  note = {Source identifier: 10015904}
}