@article{JRAM_1982__336_152469,
     author = {T.Y. Lam and M.D. Choi and Z.D. Dai},
     title = {The {Pythagoras} number of some affine algebras and local algebras.},
     journal = {Journal f\"ur die reine und angewandte Mathematik},
     pages = {45--82},
     publisher = {mathdoc},
     volume = {336},
     year = {1982},
     zbl = {0499.12018},
     url = {http://geodesic.mathdoc.fr/item/JRAM_1982__336_152469/}
}