@misc{indiciaefdc70421d41a,
  title = {Systematic method for deriving effective Hamiltonians.},
  author = {S Swain},
  year = {1994},
  doi = {10.1103/physreva.49.2816},
  url = {https://pubmed.ncbi.nlm.nih.gov/9910564/},
  note = {Source identifier: 9910564}
}