JOURNAL OF THE KOREAN PHYSICAL SOCIETY, vol. 53, no. 1, page. 461 - 465, 2008-07
JOURNAL OF THE KOREAN PHYSICAL SOCIETY, vol. 53, no. 1, page. 388 - 391, 2008-07
JOURNAL OF THE KOREAN PHYSICAL SOCIETY, vol. 49, no. 4, page. 1635 - 1639, 2006-10
JOURNAL OF THE KOREAN PHYSICAL SOCIETY, vol. 46, page. S214 - S217, 2005-06