Note: patents listed in order of most to least recent.

H.S. Freeman, C.B. Smith, M. Szymczyk, M. Zhao, “Hetero-bifunctional Reactive Dyes Comprising a Cysteamine Linking Group”, U.S. Pat. 2008216256 A1, September 11, 2008.


H.S. Freeman, J. Sokolowska-Gajda, D. Hinks, “Organic Pigments from Twisted Benzidines”, U.S. Pat. 5,965,717, October 12, 1999.


H.S. Freeman, J. Sokolowska-Gajda, A. Reife, “Iron-Complexed Formazan Dyes for Polyamide and Protein Substrates”, U.S. Pat. 5,677,434, October 14, 1997.


H.S. Freeman, J. Sokolowska-Gajda, A. Reife, “Environmentally Friendly Method for Producing Lightfast Black Shades on Natural and Synthetic Substrates”, U.S. Pat. 5,376,151, December 27, 1994.


H.S. Freeman, “Lightfast Disperse Dyestuffs”, Can. Pat. 1,325,007, December 7, 1993.


J.D. McDermed, A.S. Tadepalli, V.H.T. Chang, K.P. Hurley, H.S. Freeman, “Antihypertensive Sulfonanilides”, U.S. Pat. 5,194,450, March 16, 1993.


H.S. Freeman, “Method for Producing Lightfast Disperse Dyestuffs”, U.S. Pat. 4,902,787, February 20, 1990.