@article{10_37236_1466,
     author = {Klaus Dohmen},
     title = {On sums over partially ordered sets},
     journal = {The electronic journal of combinatorics},
     year = {1999},
     volume = {6},
     doi = {10.37236/1466},
     zbl = {0936.06001},
     url = {http://geodesic.mathdoc.fr/articles/10.37236/1466/}
}