samvermette/SVProgressHUD — pull request #147 by benoit-pereira-da-silva (2013-03-11 12:47:42+00:00)
Title: Avoid Strong Reference Cycles when Capturing self

You can Check :
http://developer.apple.com/library/ios/#documentation/cocoa/conceptual/P
rogrammingWithObjectiveC/WorkingwithBlocks/WorkingwithBlocks.html