@article{02161312, title = {Counting set systems by weight.}, journal = {The Electronic Journal of Combinatorics [electronic only]}, volume = {12}, year = {2005}, zbl = {1065.05016}, language = {en}, url = {http://dml.mathdoc.fr/item/02161312} }
Klazar, Martin. Counting set systems by weight.. The Electronic Journal of Combinatorics [electronic only], Tome 12 (2005) . http://gdmltest.u-ga.fr/item/02161312/