@article{01118076,
title = {When can the sum of },
journal = {The Electronic Journal of Combinatorics [electronic only]},
volume = {4},
year = {1997},
zbl = {0884.05003},
language = {en},
url = {http://dml.mathdoc.fr/item/01118076}
}
Petkovšek, Marko; Wilf, Herbert S. When can the sum of . The Electronic Journal of Combinatorics [electronic only], Tome 4 (1997) . http://gdmltest.u-ga.fr/item/01118076/