Well, the other day when I was trying to find info on her, this site says she invented it in 1993. The book is from 1997.
http://www.glassfacts.info/index088d.html?fid=230
I keep finding mention of a book she was writing on the HH in 2005, she was looking for artists to be in it. But I guess that never came about.
Also there is a Cindy Jenkins that passed away in September, hope it's not the same one? It just cemented my post that I know nothing about someone so innovative and invented something we almost all used at one point, if not the HH then for sure the book, that's all I see googling, 'i learned from Cindy's book", "it all started with Cindy's book."