JOURNAL OF THE KOREAN PHYSICAL SOCIETY, vol. 48, page. S179 - S185, 2006-02
JOURNAL OF THE KOREAN PHYSICAL SOCIETY, vol. 46, no. 4, page. L741 - L746, 2005-04
PHYSICA A, vol. 288, no. 1-4, page. 380 - 396, 2000-12-15
INTERNATIONAL JOURNAL OF BIFURCATION AND CHAOS, vol. 8, no. 4, page. 731 - 739, 1998-04