1. 1) Chaplits, D. N.: Japanese Patent Kokai 51-59,082 and 57-2,381, US Patent 3,965,039 (1974).
2. 2) Chiwa, M.: Japanese Patent Kokai 57-7,259.
3. 3) Fuchigami, Y.: Japanese Patent Kokai 59-12,749.
4. 5) Smith, L. A., Jr.: US Patent 4,215,011 (1979), Japanese Patent Kokai 56-130,218.