DIAMOND AND RELATED MATERIALS, vol. 15, no. 10, page. 1501 - 1507, 2006-10
JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS & EXPRESS LETTERS, vol. 43, no. 8B, page. L1106 - L1108, 2004-08-15
JOURNAL OF THE KOREAN PHYSICAL SOCIETY, vol. 45, no. 2, page. L252 - L255, 2004-08
SYNTHETIC METALS, vol. 139, no. 2, page. 385 - 390, 2003-09-05