@misc{indiciae7444a2b4740c,
  title = {A remarkable nonlinear invariant for evolution with heterogeneous rates.},
  author = {V Ferretti and D Sankoff},
  year = {1996},
  doi = {10.1016/0025-5564(95)00108-5},
  url = {https://pubmed.ncbi.nlm.nih.gov/8935956/},
  note = {Source identifier: 8935956}
}