Reference:
  Author: Yangho Chen and Tade Souaiaia and Ting Chen
  Title: "PerM: efficient mapping of short sequencing reads with periodic full sensitive spaced seeds"
  Journal: Bioinformatics
  Year: 2009
  Volume: 25
  Number: 19
  Pages: 2514-21
  DOI: 10.1093/bioinformatics/btp486
  PMID: 19675096
  URL: http://bioinformatics.oxfordjournals.org/content/25/19/2514
  eprint: http://bioinformatics.oxfordjournals.org/content/25/19/2514.full.pdf+html
