MATHEMATICAL NOTES, vol. 76, no. 3-4, page. 443 - 446, 2004-09
INTERNATIONAL JOURNAL OF MATHEMATICS, vol. 15, no. 1, page. 1 - 12, 2004-02
ADVANCES IN GEOMETRY, vol. 4, no. 1, page. 33 - 40, 2004-01
JOURNAL OF GEOMETRIC ANALYSIS, vol. 14, no. 4, page. 701 - 713, 2004-01