JOURNAL OF ALGEBRA, vol. 320, no. 5, page. 1878 - 1886, 2008-09-01
EUROPEAN JOURNAL OF COMBINATORICS, vol. 30, no. 3, page. 668 - 673, 2009-04
JOURNAL OF COMBINATORIAL THEORY SERIES A, vol. 102, no. 2, page. 255 - 271, 2003-05