@article{JIS_2010__13_2_a2,
     author = {Challis, Michael F. and Robinson, John P.},
     title = {Some extremal postage stamp bases},
     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_a2/}
}