@article{10_4064_aa109_2_7,
     author = {James G. Huard and Kenneth S. Williams},
     title = {Sums of twelve squares},
     journal = {Acta Arithmetica},
     pages = {195--204},
     publisher = {mathdoc},
     volume = {109},
     number = {2},
     year = {2003},
     doi = {10.4064/aa109-2-7},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/aa109-2-7/}
}