ELECTRONIC JOURNAL OF COMBINATORICS, vol. 15, no. 1, 2008-03-20
EUROPEAN JOURNAL OF COMBINATORICS, vol. 29, no. 7, page. 1617 - 1633, 2008-10
EUROPEAN JOURNAL OF COMBINATORICS, vol. 29, no. 2, page. 443 - 456, 2008-02
APPLIED MATHEMATICS LETTERS, vol. 21, no. 6, page. 545 - 548, 2008-06
DISCRETE MATHEMATICS, vol. 303, no. 1-3, page. 65 - 79, 2005-11-06
Discrete Applied Mathematics, vol. 146, no. 1, page. 51 - 73, 2005-02-15