@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/