If you haven't checked Master Pedro Sauer and Kid Peligro "Mastering the Closed Guard and Its Submissions" you're missing out big time. Master Sauer shows his favorite passes and a lots of great submissions. Reviews have been great so check it out.
The book is available on Kindle and in paperback version.
The book is available at www.bjjmart.com
Kid Peligro Iphone App Secrets of the Closed Guard