JOURNAL OF NON-CRYSTALLINE SOLIDS, vol. 354, no. 27, page. 3107 - 3112, 2008-06-01
GLASS SCIENCE AND TECHNOLOGY, vol. 77, page. 104 - 113, 2004-01
JOURNAL OF APPLIED PHYSICS, vol. 93, no. 12, page. 9441 - 9445, 2003-06-15