1. M. Teruo,I. Kazukiyo, and N. Tetsuo, Japanese Patent, 5,303,8709( 1978).
2. Fiber Innovation Technology, Inc., U.S. Patent 6,465,095( 2002).
3. Fiber Innovation Technology, Inc., International Patent WO 2007/1,036,2713( 2007).
4. E.I. Du Pont de Nemours and Company, U.S. Patent 4,407,889( 1983).