Joan Guzmán was a Dominican former professional boxer, and two-weight world champion, from which sanctioning boxing organization?
Joan Guzmán:  He is a two-weight world champion, having held the WBO junior featherweight title from 2002 to 2005, and the WBO junior lightweight title from 2006 to 2008. World Boxing Organization: The World Boxing Organization (WBO) is a sanctioning organization which recognizes professional boxing world champions.
World Boxing Organization