JOURNAL OF APPLIED PHYSICS, vol. 96, no. 9, page. 5110 - 5116, 2004-11-01
APPLIED PHYSICS LETTERS, vol. 84, no. 8, page. 1338 - 1340, 2004-02-23
SOLID STATE COMMUNICATIONS, vol. 129, no. 7, page. 465 - 468, 2004-02