JOURNAL OF THE KOREAN PHYSICAL SOCIETY, vol. 61, no. 4, page. 638 - 646, 2012-08
JOURNAL OF THE KOREAN PHYSICAL SOCIETY, vol. 56, no. 3, page. 982 - 985, 2010-03
JOURNAL OF THE KOREAN PHYSICAL SOCIETY, vol. 51, no. 4, page. 1432 - 1436, 2007-10