@article{02038355, title = {A combinatorial proof of the sum of }, journal = {The Electronic Journal of Combinatorics [electronic only]}, volume = {11}, year = {2004}, zbl = {1050.05012}, language = {en}, url = {http://dml.mathdoc.fr/item/02038355} }
Garrett, Kristina C.; Hummel, Kristen. A combinatorial proof of the sum of . The Electronic Journal of Combinatorics [electronic only], Tome 11 (2004) . http://gdmltest.u-ga.fr/item/02038355/