1. (to Atlas Powder), U.S. Pat. 2,387,662 (Oct. 23, 1945).
2. and (to Soc. Anonyme de Saint-Gobain) French Pat. 982,926 (June 18, 1951).
3. (to Monsanto), U.S. Pat. 2,887,507 (May 19, 1959).
4. and (to Deutsche Gold-und Silber-Scheideanstalt, A.-G.), German Pat. 926,326 (April 14, 1955).
5. Denhydag Deutsche Hydrierwerke G.m.b.H., British Pat. 788,743 (Jan. 8, 1958).