Jeffrey Lutgen. A Combinatorial Proof of an Alternating Convolution Identity for Multichoose Numbers. The American Mathematical Monthly, 123(2):192-196, 2016. [doi]
@article{Lutgen16,
title = {A Combinatorial Proof of an Alternating Convolution Identity for Multichoose Numbers},
author = {Jeffrey Lutgen},
year = {2016},
url = {https://www.tandfonline.com/doi/abs/10.4169/amer.math.monthly.123.2.192},
researchr = {https://researchr.org/publication/Lutgen16},
cites = {0},
citedby = {0},
journal = {The American Mathematical Monthly},
volume = {123},
number = {2},
pages = {192-196},
}