I've had great success spraying once with Triox, covering with black plastic, weighted down with pavers, and left in the hot Phoenix sun for a few weeks. Pull up the plastic, water the ground and put the plastic back down. Pretty much kills everything, including the earth worms. Bermuda grass is deep-rooted, though, and will continue to come back and haunt you for years once it gets a little water. Best method of erradication is to dig it up and get rid of it, roots and all. For any that still manages to survive, I spray with Ortho's Grass-B-Gone, active ingredient Fluazifop, which will kill the grass without killing my rose bushes.