Reference:
  Author: Sergei L. Kosakovsky Pond and Simon D. W. Frost and Spencer V. Muse
  Title: "HyPhy: hypothesis testing using phylogenies"
  Journal: Bioinformatics
  Year: 2005
  Volume: 21
  Number: 5
  Pages: 676-679
  DOI: 10.1093/bioinformatics/bti079
  PMID: 15509596
  URL: http://bioinformatics.oxfordjournals.org/content/21/5/676.abstract
  eprint: http://bioinformatics.oxfordjournals.org/content/21/5/676.full.pdf+html
