@article{MS2_1980__47_166712,
     author = {Ernst S. Selmer},
     title = {On the postage stamp problem with the three stamp denominations.},
     journal = {Mathematica Scandinavica},
     pages = {29--71},
     publisher = {mathdoc},
     volume = {47},
     year = {1980},
     zbl = {0436.10027},
     url = {http://geodesic.mathdoc.fr/item/MS2_1980__47_166712/}
}