@article{MAN_1979__245_163319,
     author = {T.Y. Lam and R. Elman and A.R. Wadsworth},
     title = {Pfister {Ideals} in {Witt} {Rings.}},
     journal = {Mathematische Annalen},
     pages = {219--246},
     publisher = {mathdoc},
     volume = {245},
     year = {1979},
     zbl = {0401.10032},
     url = {http://geodesic.mathdoc.fr/item/MAN_1979__245_163319/}
}