Whilst I was on vacation last week, I heard via facebook that Master Rivera had passed.

He wrote two articles for us.
Hung Gar's Monkey Staff (NOV+DEC 2012)
Hung Gar’s Monkey Staff Two-Person Fundamental Drills (MAR+APR 2015)

I never met Francisco face-to-face. We corresponded over email to publish the articles, but that was the extent of my interaction with him. Condolences to his family and friends. It's tough to lose people over the holidays.