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2. N.T. Farinacci, US Patent 2, 794, 813, (1957).
3. H.E. Mais, US Patent 3799940 (1974) assigned to Emery Industries Inc.
4. Interchemical Corporation, GB Patent 1092615 (1967).
5. Mitsui Toatsu Chemicals, French Patent 2412541, (1979).