JOURNAL OF COMBINATORIAL THEORY SERIES A, vol. 98, no. 1, page. 60 - 73, 2002-04
PROCEEDINGS OF THE AMERICAN MATHEMATICAL SOCIETY, vol. 130, no. 11, page. 3125 - 3131, 2002-01
LECTURE NOTES IN COMPUTER SCIENCE, vol. 2384, page. 190 - 202, 2002-01
ILLINOIS JOURNAL OF MATHEMATICS, vol. 46, no. 2, page. 627 - 643, 2002-01
LECTURE NOTES IN COMPUTER SCIENCE, vol. 2551, page. 285 - 295, 2002-01