1. G. Birkhoff, Representability of Lie algebras and Lie groups by matrices, Ann. of Math. vol. 38 (1937) pp. 326-332.
2. C. Chevalley, Théorie des groupes de Lie, vol. II, Paris, 1951.
3. \bysame, Théorie des groupes de Lie, vol. III, to appear.
4. Noncommutative extensions of Hilbert rings;Curtis, Charles W.;Proc. Amer. Math. Soc.,1953
5. The structure of non-semisimple algebras;Curtis, Charles W.;Duke Math. J.,1954