PHYSICAL REVIEW B, vol. 81, no. 11, 2010-03
PHYSICAL REVIEW B, vol. 68, no. 20, page. 205307 - 205308, 2003-11
JOURNAL OF CHEMICAL PHYSICS, vol. 112, no. 2, page. 723 - 730, 2000-01-08
PHYSICAL REVIEW B, vol. 49, no. 14, page. 9555 - 9559, 1994-04-01