Open Access System for Information Sharing

JOURNAL OF PURE AND APPLIED ALGEBRA, vol. 208, no. 1, page. 361 - 369, 2007-01

JOURNAL FUR DIE REINE UND ANGEWANDTE MATHEMATIK, vol. 538, page. 213 - 221, 2001-09-30

ACTA MATHEMATICA SINICA-ENGLISH SERIES, vol. 23, no. 6, page. 1083 - 1094, 2007-06

ALGEBRAIC AND GEOMETRIC TOPOLOGY, vol. 8, no. 2, page. 885 - 909, 2008-01

COMMUNICATIONS IN ALGEBRA, vol. 31, no. 12, page. 5755 - 5768, 2003-01