JOURNAL OF NON-CRYSTALLINE SOLIDS, vol. 353, no. 16-17, page. 1665 - 1669, 2007-06-01
JOURNAL OF NON-CRYSTALLINE SOLIDS, vol. 352, no. 5, page. 423 - 428, 2006-05-01
JOURNAL OF NON-CRYSTALLINE SOLIDS, vol. 246, no. 1-2, page. 128 - 135, 1999-04