Reference:
  Author: Andrew J. Page and Ben Taylor and Aidan J. Delaney and Jorge Soares and Torsten Seemann and Jacqueline A. Keane and Simon R. Harris
  Title: "SNP-sites: rapid efficient extraction of SNPs from multi-FASTA alignments"
  Journal: Microbial Genomics
  Year: 2016
  Volume: 2
  Number: 4
  DOI: 10.1099/mgen.0.000056
  URL: http://mgen.microbiologyresearch.org/content/journal/mgen/10.1099/mgen.0.000056
  eprint: http://mgen.microbiologyresearch.org/deliver/fulltext/mgen/2/4/mgen000056.pdf?itemId=/content/journal/mgen/10.1099/mgen.0.000056&mimeType=pdf&isFastTrackArticle=
