The Merck Manual: Spirochetes - Brief factsheets on spirochetal diseases. - http://www.merck.com/mrkshared/mmanual/section13/chapter157/157f.jsp
eMedicine - Yaws : Article by Natalie C Klein, MD, PhD - Yaws is a contagious, nonvenereal, treponemal infection in humans that presents mainly in children younger than 15 years. - http://www.emedicine.com/med/topic2431.htm