| http://www.w3.org/ns/prov#value | - Z is selected from the group consisting of oxygen; sulfur; ##STR7## where R is aryl (of 6 to 20 carbons, such as phenyl) or acyl (of 2 to 20 carbons, such as acetyl, benzoyl, etc.); a carbon-to-carbon bond; or ##STR8## where R4 and R5 are selected from the group consisting of hydrogen, an alkyl radical having 1 to 4 carbon atoms, and an alkenyl radical having 2 to 4 carbon atoms; and n is zero or
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