Reference:
  Author: Jeet Sukumaran and Mark T. Holder 
  Title: "DendroPy: a Python library for phylogenetic computing"
  Journal: Bioinformatics
  Year: 2010
  Volume: 26
  Number: 12
  Pages: 1569-1571
  DOI:  10.1093/bioinformatics/btq228
  PMID: 20421198
  URL: http://bioinformatics.oxfordjournals.org/content/26/12/1569.abstract
  eprint: http://bioinformatics.oxfordjournals.org/content/26/12/1569.full.pdf+html
