ADVANCED MATERIALS, vol. 14, no. 24, page. 1841 - 1843, 2002-12-17
JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS & EXPRESS LETTERS, vol. 41, no. 11A, page. L1206 - L1208, 2002-11-01
APPLIED PHYSICS LETTERS, vol. 80, no. 22, page. 4232 - 4234, 2002-06-03