Gmelin Handbook: Na: SVol.1, 71, page 297 - 307 Full Text Show Details Bader, H.-E.-R. Patent: FR921584 , 1947 ; C. (West-Germ.) I, 1948 , p. 800 Full Text Show Details Dambly, E.; Boursois, E. Patent: FR726045 , 1932 ; C. II, 1932 , p. 3651