http://www.catie.ca/en/search/apachesolr_search/HPV

CDC

             http://www.cdc.gov/std/hpv/stdfact-hpv.htm

McGill University

             http://www.mcgill.ca/hitchcohort/hpvfacts

The Anal Cancer Foundation

             https://www.analcancerfoundation.org/what-is-anal-cancer/hpv-cancer/

UCSF

             http://id.medicine.ucsf.edu/analcancerinfo/hpv/