PHYSICAL REVIEW B, vol. 89, no. 16, 2014-04-10
PHYSICAL REVIEW B, vol. 72, no. 19, page. 193309 - 193310, 2005-11
PHYSICAL REVIEW B, vol. 66, no. 23, page. 233301 - 233302, 2002-12-15
PHYSICAL REVIEW B, vol. 51, no. 24, page. 17635 - 17641, 1995-06-15