@article{10_4153_CMB_1988_028_0,
     author = {Fixman, Uri},
     title = {Sums of {Multinomial} {Coefficients}},
     journal = {Canadian mathematical bulletin},
     pages = {187--189},
     year = {1988},
     volume = {31},
     number = {2},
     doi = {10.4153/CMB-1988-028-0},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CMB-1988-028-0/}
}