@article{JIS_2010__13_2_a7,
     author = {Quaintance, Jocelyn and Kwong, Harris},
     title = {Permutations and combinations of colored multisets},
     journal = {Journal of integer sequences},
     publisher = {mathdoc},
     volume = {13},
     number = {2},
     year = {2010},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/JIS_2010__13_2_a7/}
}