@article{JIS_2009__12_7_a2,
     author = {Duncan, Bryce and Peele, Rhodes},
     title = {Bell and {Stirling} numbers for graphs},
     journal = {Journal of integer sequences},
     publisher = {mathdoc},
     volume = {12},
     number = {7},
     year = {2009},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/JIS_2009__12_7_a2/}
}