JOURNAL OF THE KOREAN PHYSICAL SOCIETY, vol. 67, no. 12, page. 2039 - 2044, 2015-12
JOURNAL OF THE KOREAN PHYSICAL SOCIETY, vol. 56, no. 3, page. 982 - 985, 2010-03
JOURNAL OF THE KOREAN PHYSICAL SOCIETY, vol. 53, no. 96, page. 3837 - 3841, 2008-12