http://www.uchospitals.edu/news/1997/19970529-cancer-mort.html
http://www.gatesfoundation.org/globalhealth/pri_diseases/hivaids/announcements/announce-040610.htm
http://www.bact.wisc.edu/Microtextbook/modules.php?op=modload&name=Sections&file=index&req=viewarticle&artid=294&page=1...