1. American Cyanamid Co., British Patent 890,148, Feb. 28, 1962.
2. American Cyanamid Co., British Patent 897,581, May 30, 1962.
3. American Cyanamid Co., British Patent 898,784, June 14, 1962.
4. American Cyanamid Co., British Patent 900,762, July 11, 1962.
5. American Cyanamid Co., Indian Patent 71,315, 1962.