JOURNAL OF THE KOREAN PHYSICAL SOCIETY, vol. 26, page. S473 - S475, 1993-12
JOURNAL OF THE KOREAN PHYSICAL SOCIETY, vol. 26, page. S396 - S398, 1993-12
PHYSICAL REVIEW E, vol. 48, no. 6, page. 4805 - 4809, 1993-12
PHYSICAL REVIEW E, vol. 47, no. 5, page. 3707 - 3711, 1993-05