Mar 26, 2008 #1 L lonlee Newbie level 3 Joined Mar 20, 2008 Messages 3 Helped 0 Reputation 0 Reaction score 0 Trophy points 1,281 Activity points 1,294 H. Richter, Z. P. Wang & L. Ley, Solid State Commun. 39, 625 (1981) thx~