@article{BUMI_1962_3_17_4_a1,
     author = {Simpson, Harold},
     title = {On tetrahedral numbers.},
     journal = {Bollettino della Unione matematica italiana},
     pages = {357--357},
     publisher = {mathdoc},
     volume = {Ser. 3, 17},
     number = {4},
     year = {1962},
     zbl = {0108.26703},
     mrnumber = {146140},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/BUMI_1962_3_17_4_a1/}
}