CHINESE ANNALS OF MATHEMATICS SERIES B, vol. 25, no. 4, page. 493 - 506, 2004-10
JOURNAL OF MATHEMATICAL ANALYSIS AND APPLICATIONS, vol. 293, no. 2, page. 663 - 676, 2004-05-15
FASEB JOURNAL, vol. 18, no. 8, page. C251 - C251, 2004-05-14
CHINESE ANNALS OF MATHEMATICS SERIES B, vol. 25, no. 2, page. 183 - 198, 2004-04
APPLIED MATHEMATICS LETTERS, vol. 17, no. 1, page. 89 - 94, 2004-01