1. S.G. Dimagno, US Patent 6,013,790 (January 11, 2000)
2. S.G. Dimagno, US Patent 6,455,510 (September 26, 2000)
3. T. Wijesekera et al, US Patent 5,571,908 (November 6, 1996)
4. M.J. Therien et al, US Patent 5,599,924 (February 4, 1997)
5. The Synthesis and Biological Activity of Certain 4'-Thionucleosides