GR510 Sentier des 8 vallées

I've seen a description of GR510 called Sentier des 8 vallées  in Provence and it looks wonderful. FFRandonnee used to have a topo-guide about this trek, but it's out of print now. Still, the trail itself seems to still exist, I have it on my GPS map, and also some Provence web pages mention it. Has anyone done it recently? Is it still possible? Is there any other guidebook covering it, French or English?

I think this is part of the Panoramique du Mercantour - GR52A....if so from a quick search a couple of places 'appear' to have that:

http://www.ikgaopreis.nl/5/0.FFRP/CR1693.ffrp_panoramique_du_mercantour

http://mapfox.de/9782751402395.php?PHPSESSID=a95ebf2de3e3c9d4c0474a188330afa8

I have this book, but it does not cover the GR510. You  can see all Provence-GR on one map here

http://www.provenceweb.fr/f/mag/outdoor/hiking/alpmarit.htm

Ok, I was wrong - this book does cover it, and this is not the book I have but the one I'd like to have... I'll check if they really  have it those two places, all other web shops don't have it anymore