Reference:
  Author: Jason Evans and Luke Sheneman and James A. Foster 
  Title: "Relaxed Neighbor-Joining: A Fast Distance-Based Phylogenetic Tree Construction Method"
  Journal: J. Mol. Evol.
  Year: 2006
  Volume: 62
  Number: 6
  Pages: 785-792
  DOI: 10.1007/s00239-005-0176-2
  PMID: 16752216
  URL: http://link.springer.com/article/10.1007%2Fs00239-005-0176-2
