EUROPEAN JOURNAL OF COMBINATORICS, vol. 29, no. 5, page. 1186 - 1199, 2008-07
JOURNAL OF COMBINATORIAL THEORY SERIES B, vol. 94, no. 2, page. 245 - 258, 2005-07
EUROPEAN JOURNAL OF COMBINATORICS, vol. 29, no. 1, page. 193 - 207, 2008-01